Stephenson's Practical Test Adjiistment and Settiii.^ of Valves riowio Maaagettie EoFiiie* Boiler and ator, ««««siLJ ^■^^^^K Chap. Copyright No. Shelf.T..3-5r'^7 . -^SB5 ■*!!?ta«B«^' GEORGE STEPHENSON STEPHENSON'S ILLUSTRATED PRACTICAL TEST, EXAMINATION AND Ready Reference Book FOR STATIONARY LOCOMOTIVE AND MARINE ENGINEERS ...Firemen, Electricians and Machinists... TO PROCURE Steam Engineer's-LiCens?^. ALSO WORKING CHART 5^6^^^ For Setting Out the Forms of Gear Teeth so That Any Two Wheels of a Set May Work Together. CHICAGO LAIRD & LEE. PUBLISHERS i \. . 1 ^ inch lower for every eight feet in length. Ques. Why is it lower? Ans. Because when there i.« water in the gauge cocks, there will surely be water a! the other end of the boiler. Ques. How many gauge cocks has a boiler? Ans. Generally tnree. 16 ' Ques. Where is the first or lower gau>ye? Ans. Two inches above the flues, and the rest two inches apart. Ques. Where is the waterline? Ans. First gauge. Ques. Where should water be in the boiler when run- ning? Ans. Second gauge. Ques. What should be done preparatory t shutting down for the noon hour? Ans. Slacken the drait, and let the steam run down, say 15 lbs or so, also let the water run down to below 2d gauge and when the engine has stopped put the feed on and clear the fires. Ques. What other duties devolve on the engineer at this time? Ans. He should examine all the journals and moving parts, refill the oil cups, etc. Ques. Where should water be carried when shutting down at night? Ans. At the third gauge and close gauge glass cocks. Ques. Why carry water so high and close glass gauge cocks? Ans. To allow for evaporation and leakage and keep water in the boiler in case glass would break. Ques. Where is the fire line of a boiler? Ans. j( of an inch below first gauge. Ques. When you open a boiler and look in, where do the scales lay thickest? Ans. Over the fire-plates. (The second sheet generally.) Ques. What causes that? Ans. The circulation and heat is greatest there. Ques. Of what use is a steam drum? Ans. To have more dryer steam in volume. Ques. How should the circulation and feed be? Ans. The circulation and feed should be continual. Ques. Whv so? Ans. Because boilers are known to have exploded immediately on the opening of the steam valve to start the engine, after the circulation in the boiler and the engine had been standing still for a short time. Qaes. Explain the cause of it. Ans, It is caused by the plates next to the fire box being overheated, and as soon as the valve is opened the pressure is lessened, and the water on the overheated sheets flash into steam and if the boiler is not strong enough, a terrific explosion is the result. Ques. If the gauge cocks were tried and there was do water in sight what should be done? Ans. Cover the fire •with wet ashes, pull the fire out, then raise the flue caps and let the boiler cool down. Ones. Why are wet ashes thrown over the fire before pulling the fire out? Ans. To lessen the heat. If the fire was stirred up without throwing wet ashes over it, it would create more heat and very likely burn the plates. Ques. What should be examined in the boiler every cleaning out day? Ans. The braces in the boiler should be examined to see if they are loose, also the sheets, flues, heads and seams, to see if they are cracked or leaking; if ihey are not attended to, they may cause ser- ious trouble and loss of life. Ques. What should engineers look after in and about the engine and boiler room? Ans. They should see that everything about the engine or boiler room is clean and all the tools are in their proper places. Also see that all valves or cocks do not leak, if so they should be ground in with emery and oil until a seat or true bearing is found. Ground glass is good for grinding brass valves. Ques. When should the boiler seams be looked after and caulked? Ans. The boiler seams should be looked after when the boiler is hot, and filled with water, to find the leaks, and the caulking should be done when the boiler is cold and empty as the jarring while caulking would have a tendency to spring a leak somewhere else, If the boiler was under pressure. 18 Ques. Is pressure and weight the same? Ans. No. Ques. Why? Ans. Because pressure forces in every direction, while weight presses only down. Outs. Which is best, the riveted or the lap-welded flues? Ans. The lap-welded flues, as they are a true cir- cle and not so easily collapsed as the riveted flues, which are not a true circle. Ques. What is meant by foaming? Ans. Foam- ing is the water and steam being mixed together. Ques. State the general causes of foaming? Ans. Dirty greasy, oily and soapy water; salt water forced into fresh water, also too much water and not enough steam room will cause foaming. Ques. What is meant by priming? Ans. Priming is the lifdng of water with steam, such as opening a valve 'suddenly, and drawing the water from the boiler to the yJinder of the engine. Ques. What should be done in that case? Ans. Close the throttle valve and leave it closed for a few minutes, then op( n the valve slowly; that will generally remedy it. Sometimes priming is caused by too much water and not enough steam room; in that case less water is car- ried. Ques. Suppose there was a high pressure of steam in the boiler and the water was out of sight, would it be safe to raise the safety valve to let off the pressure? Ans. No, under no circumstances. Ques. Why not? Ans Because it would cause the water to rise, and when the valve closed the water would drop back on the heated parts and be liable to explode the boiler. Ques. Suppose the boiler was too small to keep up the required am<.unt of steam, would it be practical to weigh down the safety valve to carry a higher pressure? Acs. No, under no circumstances. 19 Ques. Why not? Ans. Because it wOuld show care- lessness and a violation of the laws. Ques. Is there any mystery about boiler explosions? Ans. No, they are simply caused by carelessness. No man has the right to endanger the lives and property of others when he knows that he is incompetent to perform the duty required of him as an engineer, whether licen- sed or otherwise. Ques. How much space should there be between the tubes of a steam boiler? Ans. One-half the diameter of the tube itself Ques. Name the principal valve on a steam boiler? Ans. The safety valve, by all means. Ques, Where should the lower gauge cock be placed in upright boilers, any size? Ans. One-third the distance from the lop, betv/een the two flue sheets. Ques. How long a time is it considered safe to leave the engine or boiler room alone without attention? Ans. Under no circumstances should the engine or boiler room be left alone. Ques. Why not, when everything is in working order? Ans. Because no man can tell at what moment an acci- dent might occur, which if neglected might cause a ser- ious loss of life and property. Ques. State the boiling point of water? Ans. It is 212 degrees of heat. Ques. At what point does water evaporate into steam? AnvS. It evaporates at 213 degress. (Fahrenheit.) PUMPS. Ques. Name the different pumps for feeding boilers? Ans. There are many kinds, but we consider only single 20 action, Aouble action and duplex pumps for feedinjsf "boii- "irs and general use. CSee Illustration.) COMMON PLUNGER PUMP. Ques, How many valves has a single action plunger cump? Ans. Two valves, a receiving valve and a du* •^arge valve. 21 PUMP IN DBTAIL. LIST OF PARTS. — NBW LEVER MOTION FATTBRK. I Stesm Cylinder, 3 Water Cylinder. 34 Cap. ) 35 Gland, j For Valve Rod Stuff, ing Box. 3 Yoke, 4 Valve Chest. ? Steam Cylinder Head, Inside Valve Chest Head, 7 Outside Valve Chest Head, 8 Steam Piston, 9 Valve Piston, 10 Guide, 12 Water Valve Plate, 13 Water Cap, 14 Water Cylinder Head 5hing, I and, > >. ) 44 Water Piston, 45 Follower, For Pat. Fi- 46 Inside Ring, etc., brou? Ring 47 Fibrous Packing,! Packin/. 48 Seat, I 4^^ Stem I For Rubber Water 50 Spring, ( Valve. 52 Cover, I 51 Rubber Water Valve, 84 Stem, 1 85 Spring, VFor Metal Disc Valve 87 Seat, ) 86 Metal Disc Valve, 88 Bearing Stand, 89 Piston Rod Arm, 90 lycver, 91 Fulcrum Pin, 92 Tappit Block Nut, 93 Piston Rod I^ink, 94 ly-nk Pin, 95 Piston Rod Arm Bolt, 96 Piston Rod Arm Pin, 97 Lever Pin, 98 Tappit Block, 99 Gland for Stud Stufdng Box. For Piston Rodstuff-ioo Valve Rod Links, ing Box. loi Link Stud, Washer and Nut. 15 Water Cylinder Lining, 16 Main Valve, 17 Auxiliary Valve, 18 Air Chamber, 19 Piston Rod, 20 Tappit, 21 Tappit Key, 22 Tappit Set Screw, 23 Lubricator, 24 Valve Rod, 25-25-25 25 Drip Plugs or Cocks, 26 Eye Bolt and Nut, 27 Water Piston 28 Bushing, 29 Gland 30 Cap 31 Nut, 32 Flange Nut, yPor Piston Rod 33 Check Nut, ) Ques. How many valves has a double action? Ans. Four, two receiving and two discharging. The double action receives and discharges both strokes. This kind of a pump has a steam cylinder on one end. The large pumps have eight, sixteen and thirty-two small valves on water cylinder, according to the size of the pump. Ques. Why do large pumps have many small water valves and not a few larger ones in proportion? Ans, The reason the pumps have small valves is that the valves do not have to open as much as larger ones, consequently the pump does not loose the quantity of water each stroke as it would with larger valves. Ques. How are pumps set up and leveled? Ans. Pumps Are set so the receiving is from the boiler and the dis- charge toward the boiler, put in the same size receiving find discharge pipe as tapped in the pump, 90 the pump 2;; can have a good supply and discharge. The suction should be straight as possible and perfectly air tight. The pump is leveled with a spirit-level or a square and plumb line. To level a double action pump, some level across the frame and along the piston; the other way is to take the valve chamber cap off the water cylinder and level the valve seats, so the valves will rise and drop plumb. To level a single action pump, take off the valve cham- ber caps and level both ways. Ques. How are the water piston heads packed, and with what in the water cylinders? Ans. They are gener- ally packed with square canvas packing and generally takes two or three pieces; one piece is jointed on top, and the others about ^ way around to make, what engineers call, a broken joint The packing runs from X to J^ inch square. These are the general sizes used for com- mon sized pumps. Ques. How are the steam valves of duplex pumps set and adjusted? Ans. Take off the valve chest cover, shove the piston against one of the cylinder heads and mark the piston rod with a pencil at the packing-box gland, then shove the piston against the other cylinder-head and make another ma.k, find the centre between the two marks and move the piston until the centre mark reaches the packing box gland where the first mark was made. Or in other words plumb the lever that connects the valve rocker shaft and the piston. After this is done, see how the steam valve is for lead; if equal at both ends the valve is set, if not, adjust by uncoupling the valve stem at the coupling outside of the packing box, and turn to suit the adjustment in equalizing the "leado " Ques. What other valve has a pump near the boiler? Ans. A check valve. Ques. Ofwhat use is a check valve? Ans. To hold the 24 water that is forced into the boiler from coming back, in case there is any work to be done on the pump itself. loi Sieam. Cylinder. 10 ^ Water Cylinder, 103 Yoke. 104 Valve Chest. 105 Steam Cylinder Head. 106 Valve Chest Stuffing box 107 Steam Pipe. 108 Steam Piston. 109 Valve Rod Head. no Long Valve Rod Link. 1 1 1 Short Valva Rod Link. 35 it a Hand Hola plate for cap. 113 Water Cap. 114 Water Cylinder Head. 115 Water Plunger Bushing. 116 Steam Valve. 117 Plunger Bushing Ring. 118 Air Chamber and Tee. 119 Piston Rod. 120 lyOag Crank. 121 Short Crank. 122 Steam Cylinder Foot. 123 Lubricator. 1 24 Valve Rod. 125 Drip Cock. 126 Hand Hole Plate forW.C. 127 Water Plunger. 128 Plunger Bushing Stud. J29 Piston Rod Gland. 130 Piston Rod Link Arm. 131 Piston Rod Nut. 132 Piston Rod Link. 133 Piston Rod Check Nut. 134 Oil Cup. 135 Valve Rod Gland. 136 Long Lever. 137 Short Lever. 138 Pin for Valve Rod Head. 139 Lever Pin. 140 Link Arm Pin. 148 Water Valve Seat, 149 Water Valve Stem. 150 Water Valve Spring. 151 Water Valve. 152 Water Valve Cover. 162 Steam Piston Head. 163 Steam Piston Follower. 164 Steam Piston Packing Rings. 165 Steam Piston Wedge. 166 Steam Piston Packing Screw. 167 Steam Piston Spring. 168 Valve Che.<=t Cover. 169 Bearing Stand. Ques. What instructions must one give in ordering a steam pump? Ans. In ordering a pump, the buyer should inform the parties of whom he orders a pump, the follow- ing points: 1. For what purpose the pump is used. 2. The nature of the liquid to be pumped, hot, cold, salty, fresh, clear or gritty, also the largest quantity required to be pumped per hour. 3. To what height lifted and what height forced . 4. The ordinary pressure of steam used. P. S. When ordering parts for pump in use, order by proper name, also stating size of pump and manufacture, whether new or old style. Ques. Could water be forced into the boiler if there were three or four check valves on the discharge pipe? Ans. Yes, water could be forced through all,but it would be more labor on the pump. Ques. Where is a pet cock put on the pump barrel for cold water, and why? Ans. It is put at the side and near the bottom of the pump barrel, and is there to show how the pump is working, and to drain the pump in winter to prevent it from freezing. Ques, How is it known when the pump is iu goo^ 26 working order? Ans. By opening the pet cock and no- ticing the stream that comes out. Ques. How does the stream show when the pump is ic good working order? Ans. Nothing in the suction stroke and full force in the discharge stroke. (Single action.) Ques. Where would the trouble be if water came fuV* force both strokes? Ans. The trouble would be locater. at the check and discharge valves, both being caught up Ques. Where would the ti'ouble be located if water came full force both strokes, moderate, tank or hydrant pressure? Ans. At the receiving valve. Ques. Can a pump work without a check valve? Ans. If the discharge valve m the pump is in good order, it can; but if there is neither check nor discharge valve, it can not. ^ues. Can a boiler be fed without a pump? Ans If the pressure of the boiler is below the pressure of the feed water or city pressure, it can, by simply openins: a water valve and letting in the amount of water required. Ques. By what other means is a boiler fed? Ans. By an injector or an inspirator. Ques. What is an injector or an inspirator? Ans. They are devices to answer for a pump in feeding a boil- er; they draw force and heat the water at the same time. To CONNECT THE INSPIRATOR. In all cases connect so it will take steam from the highest point of boiler. Place a globe valve in steam pipe, just above the inspirator; a globe valve in the supply I oe, close to the Inspirator, and a Check and Globe valve between Inspirator and boiler. If the feed ■3 deUvered through a heater, place a check between it 9Tid the Inspirator. Blow dut steam pipe before connecting-. For a hi^V 27 lift or long draft, make the suction one size larger than HANCOCK INSPIRATOR. STEAM FEED OVERFI^OW VAI,VE UNDER FEKD. 28 TO START THE INSPIRATOR. See that the overflow valves, marked 1 and 3 are open and the forcer valve marked 2, is closed. Give full steam. After gjettiner water, close No. 1, open No. 2 one quarter of a turn, close No 3, and the Inspirator is at work. the connection. Be sure that the section pipe is absol- u ely tight. The Conditions must be: First. An Air tight Suction. Second . An abundant supply of water, with a lift not exceeding 25 feet, and a temperature not exceeding 140 degrees Fahr. for a low lift, and 110 degrees for a 25 foot lift. Do not connect with other steam pipes. Tap the boiler where you can obtain the Dryest Steam, and if you are obliged to connect with a large steam pipe, tap it on the upper side so as to avoid the drip caused by condensation in the large pipe. Do not allow boiler compositions of any kind to pass through the Inspirator. In case the Inspirator becomes incrusted with lime disconnect it and place it in a bath composed of one part of muriatic acid and 9 parts of soft water. Leave the In. spirator in the liquid over night. Ques. State the principal upon which a jet of steam taken from the boiler at boiler pressure can force a stream of water back into the boiler through the Injector or Inspirator? Ans. It acts upon the principal of a light body moving at a high velocity giving a slower motion to a heavier body effecting an entrance by means of the momentum thus given to it. For instance, steam at the pressure of 80 lbs to the square inch will escape !nto tJ»e ttir with a velocity of 1,821 feet per second or 1,241 miles per hour. This rapidly moving jet of steam causes, ai first a vacuum in the casing of the injector which fills with water. The steam then mingles with the water, condenses and imparts its velocity to it. The stream of water is then forced along the pipe and strikes the check valve with a force sufiicient to open it and then enters the boiler. Ques. Will the inspector work if the water that is sup- plied is to hot to condense the steam? Ans. No. Ques. Why? Ans. Because steam is highly elastic and bulky, and, of itself, would have no effect in driving the hot water in any particular direction. But when steam is moving at a high velocity and is condensed, these par- ticles of water have the power of driving the main body before it into the boiler. EXCEI.SIOR BOII.ER FEEDER. The principal is easily explained, for instance; if a block of wood is laid upon the water it will float, but if it is thrown violently downward it will at first go below the. surface . Th en i f there were sometliing there to catch It and hold it, we would have a state of affairs similar to the injector, where the water enters the boiler by its own jiiomentum and is held there bv the check valve. 3« DIRBCTIONS FOR CONNECTING TO THE BOII^ER. Take the dry steam from the highest part of the boiieir and connect to the coupling on top of the feeder, placing a globe valve on this at any point most convenient fot the user to work it. This valve should be kept in good ORDER so AS NOT TO BE I.EAKING STEAM WHEN NOT IN OPERATION. Attach the feed pipe to the coupling on end of feeder taking to boiler opening, place a good check valve at this point near to boiler as practicable. It is desirable in laying suction pipe to commence at the well or tank, make as few joints as possible, AS TH« WATER i^ or X i^ich gas tap as may be required to receive the oil discharge pipe. Then tap the steam pipe three feet or more above the top of the condensing chamber a-s may be required, using % inch gas pipe for steam connecting tube, which attach to top of condens- er. If, for any reason, the steam pipe can not be tapped three feet or more above the condens- ing chamber, it may be tapped lower down and the tube of re- quired length may be bent or coiled. Description of the Sectional cut; P- is the condensed water pipe. S. is the oil pipe. How to fill and operate. — Close valves D and K, open valve G, draw off the water, close valve G and fill with oil . First, open valve D, then regulate the flow of oil with valve E. In case of strong pulsation, valve N to be partially closed until oil feeds steadily; same to be closed in case of breaking feed glass. Before starting the cup, time should be allowed for sight-feed glass and condensing chamber to fill with wa- ter by condensation . 42 When there is danger from freezing, when not in usy valves D, G and E should be left open. DESCRIPTION. A — Oil Reservoir. B— Steam Pipe. C— Oil Filler. D— Water Feed Valve. E — Valve to regulate flow of oil. FF — Steam Tube and condensing cham- ber. G— Drain Valve to draw off water to prevent freezing etc. H— S'gbtFeed Glass. J — Cilass Indicator. K--Oil Discharge pipe. -N_Valve to correct pulsation or un- steadiness in feed. O— Vent. POUNDING ENGINES. SOME OE THE CAUSES THAT LEAD TO THIS TROUBI^E. Since engines of high speed and short stroke have come into general use, it is not uncommon to find many of them quite noisy. The engineer in charge of a smoothly run- ning engine takes great pride in showing it, but when a 43 click or pouudiiig is heard, he naturally feels that these defects reflect upon his skill, and whether alone or in the presence of visitors, it is a constant source of annoyance. Many hours of overwork for which he makes no charge, are emph yed in trying to locate the caiise of these noises, which to outsiders are of no consequence, but to his ear become almost unbearable. Sometimes, when the main belt is off, the engine runs so smoothly he fancies the trouble has been reached, but in the morning when the machinery is set to work the exasperating pounding be- gins, and to aggravate the case, boxes that formerly had given no trouble, begin to heat from being too closely ad- justed. There are few, perhaps, outside of the engineering pro- fession who know how perplexing a thud, or pounding in an engine becomes. Goto the cylinder and it seems to be there; stind at the crank and the noise is there. The sensitive ear of the engnieer can hear nothing else, and its continuance affects both mind and bodj^ in a way that is hard to explain. It would be as easy to prescribe one remedy for all cases of dyspepsia, as to give a rule for finding the causes of pounding in an engine . It is well known that a want of PROPER AI.IGNMENT is one of the most common causes, and every engineer worthy of the name should be able lo adjust the working parts of an engine to a line. Aside from imperfect work- manship in the erection of an engine, there are other caus- es of pounding to which we may call attention, the obscu- rity of some of these, may cause them to be overlooked. Wrist-pins in both cranks and cross-heads naturally wear unevenly, and these defects are frequently allowed to go on until the boxes will become quite loose at the dead centers, and tight at the quarter centers. Calipers ap= 44 plied to the wrists will detect these defects. Another de- fect ill wrist-pins, not so easily detected, is faulty work- manship, the wris's not being placed squarely in the crank or cross head. A good spirit level will detect the slight- est deviation in this and may be applied as follows: Dis- connect the rod from the cross head and tighten it tj the crank pin so it may turn, but not vibrate sidewise; place the rod in a position to move freely as the crank is turned; attach a spirit level to the rod with a clamp and in line with the main shaft. It matters not whether the main shaft be leveled. The position of the bulb in level should not charge when the crank is revolved. But if the wrist pin is not set square! 3% the level will be tipped from side to side, as the crank revolves, and the places the bulb oc- cupies at different points in the revolution will indicate the direction the wrist takes from that of a correct posi- tion. It will be readily seen that this tej^t detects the slightest discrepancy, as the deviation is doubled by this reversing of the position of the wrist in its revolution. It may be a matter of surprise in thus examining wrist-pins, to find how many there are that are not set PERFECTI.Y SQUARE. The power of such a wrist to strain, and open its boxes is almost unlimited and most seriously affect the running of an engine. Another fruitful cause of unsteady motion and noise in the running of an engine, is improperly balanced cranks. Much has been written on this {.abject, so we will leave it l)y merely saying that a disk cuank, in order to hold the proper amount of balance, should be several inches larger than is needed for the stroke of the engine. This we learned a number of years ago, and have siace seen that many builders of high speed engines have adopted this plan. 45 Pounding is sometimes aggravated, or in fact produced, by improperly proportioned valves. Especially is this so when engines have high speed and heavy reciprocatiug parts. The questions involved are of vital impoitance in Vhe construction of a good and economical engine, but they are too intricate to be treated here. The one feature lo which we call attention is that of the cushion. This i= to confine enough exhaust steam in the cylinder at the termination of each stroke to form a spriug as it were, to receive the impact of the piston as it is brought to a stop, [f this force is not spent on such a spring, it evidently falls on the boxes in the rod and main shaft. If such faults as these exist, they may never come to notice, but if thej' should, the engineer has no remedy, unless it be by patching the old valves, or introducing a new one. So he is not always to be censured when his engine does not run smoothlv, for these defects may indeed be chronic and have their origin in the designing room or in the workshop. Ques. What is the best way to get a Hue shaft in line without taking the shaft out? Ans. iThe best way is to use specially prepared instruments, but in absence of these a very good way is to run a line along, say 8 inches to one side of the shaft and paralled to its centre; then by the use of an ordinary level bring the shaft up level, and for side alignment use a piece of wood with one end formed to fit the shaft and the other brought to a point. By placing the curved end against the shaft and bringiu^" the shaft so that the pointed end of the stick will just touch the line along its entire length will secure a nicely running shaft provided that the couplings are bored outiji line. Very often a poorly lifted shaft in the coupler is the cause of a badly ranniag shaft, requiring extra pow- er to drive it and no amount of lining up v^ll remedy the evil. 46 LINING AN ENGINE. Ques. How would you Hue up an engine ? Ans. By stripping the engine, take ofi both cylinder heads, if con- venient; then take out the follower head, piston rings, bull-ring ; disconnect the piston from the cross-head; also disconnect the connecting rod from the cross-head and the crank pin; then take a slotted stick and place it on one of the studs on the end of cylinder furthest from the crank, then draw a fine sea-grass line over the stick and through the centre of cylinder, and attach it to an up- right stick at the other end of the bed-plate, nailed to the floor or clamped to the bed-plate; then take a thin stick, (like a lead pencil) the length of it being a half inch less than half the diameter of cylinder, and stick a pin in each end of the stick, so they can be forced in or drawn out to suit the adjustment; then centre the line at each end of the cylinder at the counter-bore from four sides. Never centre the line in the stuffing box where the piston passes through, but use the inside counter bore under all circumstances, whether* you can remove the back cylinder head or not. Some engine cylinder heads and frames are one; consequently, the head can not and must not be moved. Ques. If one counter-bore was larger than the other what should be done ? Ans. Centre it accordingly, by us- ing two centering sticl^s. Ques. Why is the counter-bore used ? Ans. Because the counter-bore is the only true bore the cylinder has that is not worn; consequently, all engineers and ma- «hinists must be governed by it in lining. 47 Ques. Wliat is a counter-bore ? Ans. A counter-bore is each end of the cylinder bored from one sixteenth to one fourth of an inch larger, from i to 5 inches long, ac- cording to the size and length of the C3'linder. Oues. Of what use is a counter-bore ? Ans.. To keep the piston from wearing a shoulder in the cylinder at each end. Ones. Why is it that the counter-bore prevents the piston from wearing a shoulder in the cylinder ? Ans. Because the piston rings just pass over the edge of the regular bore, and by so doing no shoulder can be formed in the cylinder. Ones. How are cylinders bored ? Ans. They are gen- erally bored on a regular cylinder boring lathe, which has a table that can be raised or lowered to suit. The regular bore is first bored, then the counter-bore, then the two faces for the heads. Ones. How is a shaft squared when the line is cen- trally through the cylinder ? Ans. By moving the crank- pin down to the line and seeing where the line touches the crank-pin between the two shoulders, then move the pin over to the other dead center, and see how it comes; if equal, the shaft is square. Ones. If it was out of square ]4- of an inch, what should be done ? Ans. Moi^e the out end pillow-block (or tail block.) Ques. Why not move the head-block ? Ans. Because it would alter the length of the connecting-rod, and be liable to knock out a cylinder-head. Ques. How would you level a shaft ? Ans. A shaft is leveled by a spirit level, or a plumb-line dropped past close to the line that comes through the cylinder directly m front of the center of shaft; let it drop in a bucket of 4« water to keep the plumb-bob from swaying around; then try the crank pin at both half strokes (the same principle as in squaring), top and bottom, and see how the crank pin feels the line ; if equal, the shaft is level. Ques. If the shaft was out of level, what should be done ? Ans. Simply thin or thicken the brasses, or bab- bitt the main pillow and out block bearings, whichever the case may be. Ques. How is it known if the center of the shaft is in line with the line through the cylinder ? Ans. it can be found out by placing a two-foot steel square against the crank face, under the line through the cylinder, so that the heel of the square is at the center of the shaft, and see how the square touches Ihe line; if it touches ex- actly, the shaft is in line ; if too hard, the shaft is too high ; if not at all, the shaft is too low. Ques. How is the shaft raised? Ans. There are various ways: by liners, babbitt, heavier or lighter brasses. Ques. If the crank was oval and a square was put against it, would that be right ? Ans. A spirit level could be placed on the square and bring it level, or drop a plumb-line, and put the end of the square against the crank-shaft center, and let it come against the plumb-line. This is a very true way. Ques. Now, after the shaft is in line, square and level, and is still out over the line % of an inch, how could it be remedied ? Ans. Simply take it off the crank pin brasses and fill in the other side with a brass ring, or babbitt the side edge of brasses; in some cases the sides of the connecting rod has to be chipped to allow it to pass free of the crank-face. Ques. Why could it not be taken off the wrist-pin grasses in the cross head ? Ans. Because the rod would 49 then be out of the center of the cross-head and have* tendency to bind the piston in the cylinder and the cross-head in the guides, consequently cutting both. Ques. Would it not make a diflference at the other end of the rod ? Ans. No, the closer the crank face the bet- ter it would be. Ques. Now what should be done ? Ans. Level and line the guid es by putting them in their place, and line them with a pair of calipers, by calipering them at both ends to get < Uem in line with the line through the cylin- der, atler h^^ving found the distance between the side of the cross-bettd and the center of the cross-head where the piston enters the cross-head. Level by spirit level, first taking spirit level and trying it in cylinder, if a new one, or on top ot the cylinder %/here it has been planed off when first bored, for they are the only things to go by. Ques. Could the valve seat be used to level by ? Ans. No, but tilongside of it, where the steam chest rests on. Que.'i. If you had no spirit level, how would you doit? Ans. With a plumb-line, by placing a square lengthwise on the guides, and try them by bringing the square against the line Que**. If no two-foot square could be had, how could one be layed off" Ans. Take a pair of dividers, draw a circle, then find four points on the circle, scribe lines from point to point, which gives a square. This should be done very accurately, or 6,-8 and lo a triangle. Ques. Explain the use and figures on a steel square ? Ans. The standard steel square has a blade 24 inches long and 2 inches wide, and a tongue from 14 to 18 inches long and 1% inches wide. The blade is exactly at right angles with the tongue, and the angle formed by them n*i exact right angle, or square corner. A proper square 50 should have the ordinary divisions of inches, half inches, quarters and eighths, and often sixteenths and thirty* seconds. Another portion of the square is divided into twelfths of an inch; this portion is simply a scale of 12 feet to an inch, used for any purpose, as measuring scale, drawing, etc. The diagonal scale on the tongue near the blade, often found on squares, is thus termed from its diagonal lines. However, the proper term is centesimal scale, for the reason that by it a unit may be divided into 100 equal parts, and therefore any number to the looth part of a unit may be expressed. In this scale A B is one inch; then if it be required to take 73-100 inches, set one foot of the compass in the third parallel under one at E, extend the other foot to the seventh diagonal in that parallel at G, and the distance between B G is that re- quired, for K I^ is one inch and P' G 72 parts of an inch. Upon one side of the blade of the square, running par- allel with the length, will be found nine lines, divided at interval? of one inch into sections or spaces by cross lines. This is the plank, board and scantling measure. On each side of the cross lines referred to are figures, sometimes on one side of the cross line and often spread over the line thus: i | 4 — 9 | . We will suppose we have a board 12 feet long and 6 inches wide. Looking on the outer edge of the blade we will find 12; between the fifth ana ^^*xth lines, under 12, will be found 12 again; this is the lengiii -^fthe board. Now follow the space along towards the xkj^^ ^-"e till we come to the cross line under 6 (on the edge of the ►.'^de), this being the width of the board; In this space will u? found the figure 6 again, which is the answer in board mcci?ure, viz., six feet. On some squares will be fouud on one side of the blade 9 lines, and crossing these lines diagonally to the right are rows of figures, as seven is, seven 2s, seven 3s, etc. THs is another style of board measure and gives the feet in a board according to its length and width. In the center of the tongue will generally be found two parallel- lines, half an inch apart, with figures be- tween them; this is termed the Brace Rule. Near the ex- treme end of the tongue will be found 24-24 and to the right of these 33-95. The 24-24 indicate the two sides of a right-angle-triangle, while the length of the brace is indicated by 33-95. This will explain the use of any of the figures in the brace rule. On the opposite side of the tongue from the brace rule will generally be found the octagon scale, situated between two central paralell lines. This space is divided into intervals and numbered thus: 10, 20, 30, 40, 50, 60. Suppose it be- comes necessary to describe an octagon ten inches square; draw a square ten inches each way and bisect the square with a horizontal and perpendicular center line. To find the length of the octagon line, place one point of the compasses on any of the main divisions or the scale and the other leg or point on the tenth subdivision. This length being measured off on, each side of center lines, touching the line of the octagon will give the points from which to draw the octagonal lines. The size of the octa- gon must equal the number of spaces taken off from the tongue by the compasses. Ques. Can a plumb-line hangout of true? Ans. It can not, provided it hangs clear of everything. If none ol these were handy, a straight edge must be placed across the guides at one end, and see if the guides touch the straight edge equally at both edges, then caliper the distance between the line and the straight edge, also at the other end of the guides ;if the same, the guides are level lengthwise with the cylinder and line; then level the guides crosswise with a plumb-line and square. Ques. How is the measure of the connecting rod of an engine found? Ans. By finding the striking points. Ques. How is that done? Ans. By shoving the pis- ton and cross-head up against the cylinder-head, and making a mark on the guides at one end of the cross- head with a scriber and center-punch; then move the piston and cross-head back to the other cylinder-head and make another mark on the guide at the same end of the cross-head; then measure from the center of the crank-pin to center of the shaft: that gives the half-stroke; double this, gives the full stroke. If half- stroke is 12 inches, the full-stroke is 54 inches; then if the distance between the two striking points is 25 inches, add the stroke 24 inches, the clearance between the cyl- inder-head and piston-head will be Yz inch when the piston is at either end of the cylinder. Then move the cross-head Yz inch back from the striking point, and bring the crank-pin toward the same dead center; then tak« a tram and measure from the uutside center of crank- pin to the outside center of wrist pin in cross-hearl, 53 which will give the proper length of the connecting-rod, also the right division of clearance. Ques. What is meant by the clearance in cylinders ? Ans. It is the unoccupied space between the piston-head cylinder-head and valve-face, when the crank-pin is at either dead center. Ques. Does the amount of clearance affect the engine ' s economy? Ans. Yes, it does. Ques. How much clearance should there be between the piston and cylinder-head ? Ans. It depends upon t^ie size; Some have from X to J^ of an inch. Ques. What is formed in that space or clearance when nmning? Ans. A cushion. Ques. What is a cushion ? Ans. A cushion means the steam that enters the cylinder through the lead the valve has, and the resistance it makes on the piston-head cylinder-head and valve-face as the engine is reaching the dead-center. Ques. What is the cushion for ? Ans. It is to catch the piston and weight of the machinery as it reaches the dead-center. Ques. How is the connecting-rod shortened or length- ened ? Ans. By placing tin or sheet iron liners between the brasses and stud-ends of the connecting-rod. Ques. Now, if the key had to be raised, how could this be done ? Ans. By putting liners between the straps and brasses. Ques. Would that not altar the length of the rod ? Ans. No. Ques. With what tool is a connecting-rod measured ? Ans. It is called a " tram." Ques. With what is an engine packed in the stuffing- box ? Ans. Some engineers use hemp, others use black 54 lead packing, and others use lead rings or metallic pack- ing; there are several kinds. Every engineer to his own taste. VALVE MOTION. Ques. What is an eccentric ? Ans. An eccentric is a subterfuge for a crank; it is anything out of center. Ques. How is the throw or stroke of an eccentric de- termined ? Ans. By measuring the heavy and the light side; the difference between the two is the stroke or throw. Ques. What throw should a common slide valve en- gine eccentric have ? Ans. Generally double the width of the entry or steam ports. Ques. What is a cam ? Ans. A cam has no definite meaning; it has i, 2, 3 or 4 motions; they are used on poppet valve engines, used on high pressure river steam- boats. Ques. How are the valves and eccentric rods of an engine found ? Ans. By placing the crank pin at its dead-center, the center of the eccentric straight or plimib above the center of the shaft, the rocker-arm perpendic- ular, and the valve covering both parts equally; then take a tram and measure from the center of the eccentric to the center of the pin where the eccentric rod hooks on (generally the lower pin) for the eccentric rod. and from the outside center of ttie pin where the valve rod is at- tached to the furthermost end of the valve allowing for two nuts at each end of the valve, called adjusting and jamb nuts. Ques. How is an eccentric brought plumb ? Ans. By dropping two plimib lines, one at each side of the shaft, and half the space between the two lines will be where the center of the eccentric should stand, with heavy side up. 55 Ques. What kind of a tool is used to find the exact center? Ans. A pair of hermaphrodite calipers, one le, of which has a sharp point and the other leg has a short foot, so as to feel the line. Ques. What does an eccentric rod consist of?. Ans. An eccentric i od consists of a strap, yoke, rod and two nuts; when taking the measure, couple the yoke and the strap toget,:er, then put a half-inch thick piece of wood between the two straps and find the center of the circle from four sides, with a pair of hermaphrodite calipers, then put the rod in the yoke and adjust it to the proper length by the two nuts; if that will not do, the rod must be shortened or lengthened, by cutting out or adding a piece, whichever the case may be. Then take the meas- ure with a tram from the center of the straps to the cen- ter of the rod where the rod hooks on lower rocker-arm pin. Ques. How long is the thread on a valve-rc>d ? Ans. Long enough to allow two nuts at each end of the valve, and space for adjustment. Ques. Now, if the rocker-arm stood at a quarter, and the eccentric out of plumb, how could the measure for the rods be taken? Ans. Simply bring them plumb and take the measure; that is the only right way. Ques. After measuring the rods what should be done ? Ans. They should be put on and the valve set. Ques. How is a valve set after the connections are made? Ans. Move eccentric in the direction the en- gine is to run, until the valve begins to take steam or lead, then tighten the eccentric temporarily with the set screws, then move the crank-pin over to the other dead center, and see how much lead the valve has; if equal, the valve is set. 5« Ques. What is meant by the lead of the valve ? Ans. The opening the valve has when the piston is at the be- ginning of its stroke. Ques. What lead should a large engine have ? Ans. About 1-16 of an inch. High speed engines must have a quick opening or good lead. Qnes. Now if you find the valve laps out )i of an inch on one end, and the proper lead on the other, what would you do ? Ans. Divide the difference, by moving the valve one-half it is out, by adjusting the valve-gear. Ques. How much ? Ans. The valve has 1-16 of an inch lead at one end and laps ^ of an inch at the other end; the valve is out 7-16 of an inch; then the valve must be adjusted by the nuts one-half it is out, making 7-32 of an inch. Then throw the crank on the other dead center, move the eccentric whichever way will bring the valve Dack to 1-16 of an inch lead, then tighten temporarily with the set screws, throw the crank over on the other dead center, and the valve will be set. After the valve is set, tighten the eccentric for good. Ques. Butifitisnot set, what would you do? Ans. Go through the same performance until it is set. Some valve-rods have a yoke that slips over the valve, while the adjusting and jam-nuts are between the stuffing box and the rocker-arm pin. When a valve-rod has no nuts, the adjusting must be done at the eccentric-rod. Ques. How is the stroke of the valve-rod shortened or lengthened ? Ans. To lengthen or shorten the stroke of the valve-rod, raise or lower the eccentric-rod pin in the slot, at the bottom of the rocker-arm, whichever way suits the circumstances. Ques. Supposing the valve had to be set in a hurry, how could it be done without seeing the valve ? Ans. Sim- ply set the valve by the cylinder cocks. 57 Ques. Now after having set the valve, keyed every- thing up properly, and there was a thud or dead sound in the engine or cylinder, where would the trouble most likely be ? Ans. In the exhaust being choked. The steam chest cover should be taken off, then uncouple the valve, turn the valve up sideways and move it until the steam edge has the proper lead with the steam-port, then place a square on the valve-seat of the cylinder, and against the valve-face, to see how the exhaust head on the opposite steam-port corresponds. If it is choked, then scribe it by allowing a little over double the steam lead. Ques. How is the exhaust made larger in common slide valve engines ? Ans. By chipping out the exhaust cavity in the valve, and rubbing a file over it to smooth it. Ques. Is a little over double the steam-lead sufficient for the exhaust ? Ans. Yes ; if not, take out a little more. Ques. Where should the exhaust be ? Ans. It should be the furthest from the steam port that is receiving. Ques. What amount of lap should the valve have to cut off steam at a given point of the stroke of the engine? Ans. Srnpi ose the valve is to cut off steam at ^ of the stroke of the engine ; the piston should be moved ^ of its stroke, th^n see how much opening the valve has; as much opening as the valve has, is the amount of lap re- quired to be added to the valve in order to cut off steam at f^ of engine stroke. This rule answers for all cut offs. Ques. What should be done in case the eccentric slipped around on the shaft ? Ans. Set the valve the same as before. Ques. Is the principle of valve setting the same on all engines ? Ans. Yes, the principle is the same. Ques. How is the dead center of an engine found ? 5S Ans. By placing a spirit level on the strap that goes around the brasses that connect the crank-pin to the connecting-rod, and when it is level the crank is at a dead center. If the engine is not level, then use an ad- justable level. Ques. By what other way is the dead center of an en- gine found ? By moving the engine toward the dead center until the cross-head stopped moving; then put a center punch mark in the floor, and one on the fly-wheel, after having marked it with a tram; then move the crank over the center until the cross-head begins to move, then put another mark; the middle between the two marks is the exact dead center; then bring the middle mark to the point of the tram; this is done with a small tram with one straight point and a short foot. Ones. If the engine had to be run in the opposite di- rection to which it had been running, how could it be done ? Ans, It could be done by placing the crank- pin on the dead center, removing the steam -chest cover, and turning the eccentric over on the shaft in the opposite direction, until the valve has the proper lead at the op- posite port, then try the engine from dead center to dead center, to equalize the lead at both ends of the valve; then the engine will run in the opposite direction. Ques. Does a crank -pin and piston travel the same distance? Ans. No, a crank-pin travels 1.1416 times further than the piston each revolution, or 0.5707 times further each stroke. For example, take an engine with a 12-inch stroke, the piston travels 24 inches and the crank pin 37.6992 inches each revolution, or the piston travels 12 inches each stoke and the crank-pin 18.8496 per single stroke of piston. To do this, multiply the single stroke by one-half of 3.1416, which is 1,5708, and the answer will be the distance the crank-pin travels fur- 59 ther than the piston per single stroke. This rule an* swers for all engines. Another fact, not generally known by many men is that a crank of an engine, at two certain points travels a long distance while the motion of the cross-head is hardly noticed. When the center of the crank-shaft and crank-pin are in a line with the piston- rod, no steam pressure applied to either side of the piston can set the engine in motion; this is called the dead center. Ques. Is the piston -head in the center of the cylinder when the centers of the crank-pin and crank-shaft are plumb, or in right angles with the cylinder ? Ans. No, under no circumstances. Ques. What is a revolution ? Ans. It means that the crank has turned once around, or made a circle. Ques. How many strokes has a revolution ? Ans. Two to each revolution. Ques. If an engine has 36 inches stroke, and makes 80 revolutions per minute, how many feet does it travel in a minute ? Ans. 36 inches multiplied by 2 equals 72 inches, this multiplied by 80 revolutions equals 5760 inches, which divided by 12 equals 480 feet per minute, Ques. If asked the horse power of any sized engine, could you tell it ? Ans. Yes. Ques. Well, how would you go about it, and what is a horse power ? Ans. A horse power is 33,000 pounds raised i foot high in i minute, or 150 pounds raised 220 feet high in one minute. To find the horse power of any engine, first find the area of the piston-head face, then multiply the answer by the average pounds pressure per square inch in cylinder, then multiply by the number of feet traveled in i minute, and divide by 33,000. 6o Cylinder 12 x 24 in. 65 revolutions. Average pressure 40 lbs. Note. — The mean or average pressure in the cylinder is less than the pressure in the boiler, since the entrance of steam to cylinder s cut off before the stroke is completed. Hence the steam in the cylinder will expand and con- sequently diminish in pressure towards the end of each stroke. Generally allow about J^ the boiler pressure in figuring the H. P. EXAMPLE: 12 12 lbs. 144 .7854 diam. of cylinder, sq. of diameter. 113.0976 area op p. h. face. 40 averag pressure in the cylinder. 4523.9040 260 No. ft. trav. by p. 33000)1176215.0400(35.9428 I. H. P. A HORSE^S POWER. MECHANICAI< INTERPRETATION OI? THIS UNIT OF MEASURE. The question is often asked: What constitutes a horse- power It is generally known to be a unit of measure as applied to steam, water, electricity, or any other energy that can be converted into useful effect. Yet the means employed for giving definiteness to the expression are not so generally understood. The term, doubtless, came into use with the introduction of the steam engine^ and a mechanical equivalent has been universally accepted, which is expressed in foot-pounds, that is to say, 33,000 lbs. raised one foot in a minute, constitute one horsS' power. 6i To those not fkmiliar with the principles of mechanics this may not be intelligible. Some simple examples and illustrations may, therefore, be allowable. Force or weight, and motion are inseparable in estimating the power which a moving body may exert, and these two factors, being equal in value, their order may be reversed without affecting the result. For example, one pound raised 33,000 feet in a minute represents a horse power as perfectly as if the feet were pounds, as in the first rule given, the power being better suited to the calculation of the power of steam, on account of its great force. We will first compare the rule with the actual powers of a horse, and thee apply it to the steam engine, for which it has been established. The usual traveling gait of a horse, hitched to a light vehicle, is about five miles an hour, or 440 feet per minute. Now, if we attach a scale to the singletree we may note the amount of power the horse is exerting. Assuming this to be 75 lbs. the product of the speed per minute, 440 by 75, gives us 33,- 000, which in dynamics, is called foot-pounds, and rep- resents a horse-power. In applying this to a steam engine we have first to de- termine the area of the piston, that is, the number of square inches it contains; and next, the average pressure of steam applied to it, which is termed the mean effective pressure. The steam gauge at boiler gives no evidence of what this may be but an instrument called an indicator attached to a cylinder, gives it exactly, and it is often a matter of surprise to find only 20 or 30 lbs. per square inch, when the steam in the boiler is held at 80 and 90 ibs. Practice with this instrument has also shown that when ordinary slide valve engines are worked to their maximum capacities, the average pressure on the piston isonly about half that of the boiler pressure, and if by 62 retson of a short valve, the average pressure is increased, it is done at a great sacrifice in the ECONOMY OF STEAM. We speak of this curtailment of pressure because so many In applying the rules we are about to give, assume too high a pressure in estimating the power of their en- gines. The next step in the calculation is to determine the speed of the piston when the engine is at its regular work. We will take an engine of 20^'' stroke, making 150 revolutions per minute. The piston travels \o'' or 3^ feet at each turn. The piston speed is therefore 500 feet per minute. We inow have all data necessary for the calculation, except the average piston pressure, which we will assume to be 30 lbs. on a 10 inch piston. The area of this is 78.54 square inches. The formula, then will stand thus. 30X78.54X500 = 35.7 H. P. 33,000 It will be seen that the total pressure on the piston is 23.56.2 lbs., which, moving at the rate of 500 feet per minute, make 1. 178.100 foot-pounds, and every 33,000 of these is a horse power Hence, to divide by 33,000 gives us 35.7 H. P. It is sometimes found convenient to omit the first fac- tor of pressure and make this a unit. We then get the H. P. of the engine for one pound to the inch, which in this case is 1.19 horsepower. We may now multiply this by any number of pounds we may secure. In case it be 30 we have the result 35.7 as before; if 40 lbs. we have 46 6 horse-power? 63 THE INDICATOR. ( Thompson'' s The steam engine indicator is an instrument for saow ing the pressure of steam in the cylinder at all poir.xs of the stroke, or for producing actual diagrams. The indi- cator consists of a small cylinder accurately bored out, and fitted with a piston, capable of working in the ( indi- cator) cylinder with little or no friction, and yet be prac- tically steam-tight. The piston has an area of just }4, of a square inch, and its motion in the cylinder is 25-32 of an inch. 64 The piston-rod is connected to a pair of light levers, so linked together that a pencil carried at the center of the Jink moves in nearly a straight line through a maximum distance of 3^ inches. A spiral spring ^.laced in the cylinder above the piston, and of a strength proportioned to the steam pressure, resists the motion of the piston; and the elasticity of this spring is such that each pound of pressure en the piston causes the pencil to move a cer- tain fractional part of an inch. The pencil in this case is made of a piece of pointed brass wire, which retains its sharpness for a considerable time, and yet makes a well- defined line upon the prepared paper generally used with the indicator. The paper is wound around the drum, which has a di- ameter of 2 inches, and is capable of a semi-rotary mo- cion upon its axis to such an extent that the extreme length of diagram may be 5)4 inches. Motion is given to the drum in one direction, during the forward stroke of the engine, by means of a cord connected indirectly to the cross-head of the engine, and the drum is brought back again during the return stroke of the engine by the action of a coiled spring at its base. The conical stem of the instrument permits it to be turned around and fixed in any desired position, and the guide-pulleys attached to the instrument under the paper drum may also be moved around so as to bring the cord upon the drum-pulley from any convenient direction. The upper side of the piston is open to the atmosphere; the lower side may, by means of a stop-cock, be put into . communication either with the atmosphere or with the engine cylinder. When both sides of the piston are pressed upon by the atmosphere, the pencil, on being brought into contact 6$ with the moving paper, describes the atmospheric line. When the lower side of the piston is in communication with the engine cjdiuder, the position of the pencil is de- termined by the pressure of the steam existing in the cylinder; and on the pencil being pressed against the paper during a complete double stroke of the engine, the entire iudicat(»r diagram is described. In order that the diagram shall be correct, the motion of tlie drum and paper shall coincide exactly with that of the engine piston; second that the position of the pen- cil shall precisely indicate the pressure of steam in the cylinder; third, that the pendulum must be from i}i to 3 times as long as the stroke of the engine piston; fourth, that the pendulum must be plumb when the piston is at half-stroke; fifth, that the cord around the drum must be attached to the pendulum at right angles, or square with the indicator; sixth, the pendulum must be attached with an inch wooden pin to the ceiling or floor at one end, the other end to the cross-head by means of a screw bolt in wrist-pin and a slot in the pendulum; seventh, that the two holes tapped in the cylinder are directly opposite the steam ports, and centrally between the piston head and cylinder head, when the engine is at the dead center, or, in other words, in the center of clearance; eighth, that the piping should be as short as possible, and ^z inch pipe if not over i foot long. If longer the pipe should be larger close to the cylinder, and covered so as not to allow too niuch condensation, as it aflfects the diagram. The best fvtiy to take a diagram is to tap a hole in each cylinder- head and take each end separately. The cord must be attached to the pendulum, so the paper drum will move in proportion to the piston. An indicator shows the highest and the lowest pressure reached, also the cut-off and lead. If there is a great 66 difference, say more than 5 pounds, between the boiler pressure and the initial pressure upon the piston, the connecting pipes may ba taken as being too small, too abrupt or the steam ports too contracted. The full pres- sure of steam should come upon the piston at the very be- ginning of its stroke. Should the admission corner be rounded, the valve is wanting in "lead," or, in other words, the port for the admission of steam is uncovered too late in the stroke. The steam line shoud be parrallel or straight with the atmosjfheric line up to the point of cut-off, or nearly so. (the steam line) fall as the piston advances, the opening tor the admission of steam is insufficient, and the steam is ' * wire-drawn . " The f oint of cut off should be sharp and well defined^ should it be otherwise, the valve does not close quick enough. The bevel line leading from the cut-off line to the end of the stroke is called the expansion line. Q. Which is the standard indicator ? A. The Thompson's improved. Q. Are there any other makes ? A. Yes: Richard's, McNought's, Tabor's and others. RULES, RUI.E) for telling the power of a diagram: Set down the length of the spaces formed by the vertical lines from the base in measurements of a scale accompanying the indi- c^tor,and on which a tenth of an inch usually represents a pound of pressure; add up the total length of all the spaces, which will give the main length, or the main pressure upon the piston in pounds per square inch; to do this, lay a card taken by the indicator off in ten parts, by drawing lines from top to bottom. Find out what the scale is; suppose it is 6oj the number of ordinates 10, and 67 that the sum of their length is 6 inches; so 6 and lo or- dinates = ()-io or 6 x 6o = 36.0. Ans. 36 pounds pres- sure upon the piston. RuivU for finding and deducting friction: Multiply N. H. P. by .13 and subtract the answer from N. H- P.. which gives I. H. P. Ques. WhatisN. H. P? Ans. It is nominal horse- power. Ques. What is I. H. P ? Ans. It is indicated horse- power. Ques. What is meant by cutting off steam at 6 inches ? Ans. It means that the valve closes and cuts off the live steam from the boiler at 6 inches of the piston's travel; then the engine gets its power from the time the valve closes or cuts off until the exhaust opens by the expansion of the steam closed up in the cylinder. Standard multiplen*, with examples: 1. For the Area of a Circle. Multiply sq. of diam. by .7854 2. ForCircumferenceofa Circle, Multiply diameter by 3.i4it> 3. For Diameter of a Circle, Multiply the circutn. by .31831 4. For the Surface of a Ball, Multiply sq. of diam. by 3.1416 5. For the Cubic Inches in a Ball.Multiply cube of dia. by .5236 1. RUI.E for finding the area of any circle. Always multiply the diameter by itself, then by .7854, then cut off 4 decimals from the right. 2. Rui,s for finding the circumference of anything round. Multiply the diameter by 3. 1416, and cut 4 deci- mals. 3. Rule to find diameter of circle. Multiply circum- ference by .31831. EXAMPI.E: The circumference 9.4248 x .31831 = 3.000008088 = 3 inches diameter. 4. RuivE to find the surface of a sphere, globe or balL ExAMPTvE: 9 inches diameter x 9 == 81 x 3.1416=: 254.4696. 68 5. Rui#B to find the cubic inches in a ball. Multiply mbe of the diameter by .5^36 the answer equals its solid rontents. ExAMPi^K: Ball 3 inches in diameter; 3x3 = 9; 9x3 --=:. 27 X .5236 =14. 1372 solid contents. Rui^ tons strain. Rui^K to find the number of feet of i inch pipe required to heat any size room with steam. For direct radiation I lineal foot (straight foot) to 25 cubic feet of space. For indirect radiation, i lineal foot to 15 cubic feet of space. Note, all pipe is measured inside for size EXAMPLE. Room 18 X 18 X 18 to b3 heated with I inch pipe. Di- rect radiation. All circulating must be done in inches, and divided by 1728 to find the cubic feet 2l6 2l6 46656 216 1728)10077696 cubic inches. 25)5832 cubic feet I/ineal 233/g feet of i inch pipe. One cubic foot of boiler is required for every 1500 cubic feet of space to be warmed. One horse power of boiler is enough for 40,000 cubic feet of space. Ruiyie to find the horse-power of boilers. Always find the number of square inches and divide by 144, which gives the square feet of heating surface, and divide by 15 square feet for flue boilers, 12 sq. feet for tubular, and 7 sq. feet for cylinder boilers, which is an average allowance for one horse power of boilers; divide the H, P. by 2, you will have th^ proper grate surface, and allow %. sq. inch of safety valve to each square foot of grate surface. Generally, from yiX-o^i oi2L square foot of grate surface is allowed to each horse power of a boiler. The H. P. of a boiler is to soai3 extent a misnomer. It is the engine which furnishes the H. P.; the boiler furn- ishes the steam to make it. A high-grade compound condensing engine will develop a H. P. with fifteen pounds of steam per hour; an ordinary non-condensing mill engine requires thirty. The engines of Watt's time required sixty or mDre. A boiler which would furnish 3000 lbs. of steam per hDur would with the last class of engine, produce fifty H. P.; with a non-condensing en- gine, one hundred H. P. ; and with a compound engine, 11 two'hundred H. P. Watt, basing the estimate upon the consumption of his engines, established the rule of a cubic foot of water per H. P. per hour, but the accepted standard at present, based upon the consumption of the average non-condensing mill engine, is thirty pounds of water from feed water at ioo° F. into steam at seventy pounds gauge pressure; equivalent to thirty-four and a half pounds of water evaporated from an atd 212° F. A common custom among boiler makers has led to the rating of boilers by horse-powers, and while no special harm has come of this, yet it is evidently a misnomer as applied to a boiler, separate and apart from an engine, for the simple reason that a boiler of a capacity suited to a 100 horse power Corliss engine, would only produce about 63 H. P. if attached to a slide valva engine cutting off at four-fifths of its stroke. In the first instancs, 3 gallons of water evaporated per hour, produce one horse- power, and in the second, 5 gallons are necessary. To add to tha confusion produced by these differences we have another unsettled quantity in the rating of boiler pow^r; namely, the amount of heating surface necessar}^ to a horse-power. The raage of difference varies from ro to 15 square feet, and practice shows that either may be right. For the amount of draft, or intensity of the heat in the furnace will determine this, as, for example, the heat is so great in a locomotive fire-box when the exhaust is strong, that 8 square feet or less of that sur- face produces a horse-power, and the consumption of coal may run as high as 50 pounds to a square foot of grate surface per hour, while in many furnaces it is reduced to 10 lbs. From so wide a range in the amount of heating surface and the difference in the consumption of fuel by forced 7S draft, it is evident that when boiler capacity is increased in this way it is done at the expense of fuel. If we are to make this matter of economy a considera- tion in the production of steam power, then the true measure of efficiency in a boiler must be its ability to evaporate the greatest amount of water with the least amount of coal or other fuel. The very best results at- tained in common practice is lo pounds of water evapora- ted with I lb. of coal, but 8 lbs. is usually satisfactory. All these varying conditions get us into a dilemma when we come to propose a standard unit for boiler ca- pacity, and as has been said of the jury system, we should let it alone until we can propose something better than horse-powers. We think good may result from drawing a well defined line between the source of power, the boiler, and the means of application of this power, the steam engine. They are too often treated as a whole, and as a result good or bad performance cannot be accurately located. Appliances are now being introduced for determining the efficiency of boilers, but much remains to be done to simplify them so as to be of general utility. Rui^Ei to find the horse-power generated in any kind of boiler when running. First, notice how long it will take to evaporate one inch of water in the glass gauge, divide this into 60, which gives the number of inches evaporated in one hour; second, multiply the average diameter where evaporation took place by the length of the boiler in inches; this multiplied by the number of inches evap- orated, and the answer divided by 1728 gives the cubic feet of water evaporated in one hour. As a rule, i cubic foot of water evaporated is generally allowed for one horse-power; also the capacity of a pump or injector for any boiler should deliver one cubic foot of water each horse power per hour, and aa engine uses ofle- ihird of a cubic foot of water per horse power. EXAMPLE: Length of boiler 216 inches. 216 Average diam. 40 inches. 40 One inch evaporated in 15 min. 8640 15)60 4 4 1728)34560(20 horse power. Weight of Sq. Superficial Foot of Boiler Plate when Thickness is Known. THICKNESS. I WEIGHT. | I THICKNESS, j WEIGHT. .03125 .0625 .0937 .125 .1562 .1875 .2187 .25 .2812 lbs 1.25 2-519 3.788 5-054 6305 7.578 8.19 10.09 11.38 Inches. Dec. lbs. 1^6 = .3125 12.58 1 = .375 15.10 /e = -4375 iyA'i i = .5 20.20 A = .5625 22.76 i = 625 25.16 f = .75 30.20 1 = .875 3530 r = .1 40.40 Ques. Explain how the above fractional parts of whole numbers are made to read as decimals — take ^q of an m. for an example ? Ans. To do this take 100 as a whole .number; divine 16 into loo = 6}{, reads .625 = ^^g ot TOO. ^g would read, 3 x .625 = .1875. This principle answers for all the rest. So- WEiGHT OF A CUBIC FOOT OF EARTH, STONE, METAL, &C. Article Lbs. Alcohol........... ^., 49 Ash Wood . 53 Bay Wood 51 Brass, gun metal 543 Brandy 58 Beer „ 65 Blood 66 Brick, common 102 Cork 15 Cedar 35 Copper, cast 547 Copper, plates 543 Clay 120 Coal, Lehigh 56 Coal, Lackawanna. 50 Cider 64 Chestnut 38 "Ebony 83 Karth, loose 94 Glass, Window 165 Gold ., . ...1,203^ Hickory, pig-nut 49 Hickory, shell-bark 43 Hay, bale 9 Hay, pressed 25 Honey 90 Iron, cast 450 Iron, plates 481 Iron, wrought bars, 486 Ice 57^ Lignum Vitee Wood 83 Logwood 57 Article. Lbs. Lead, cast 709 Lead, rolled 711 Milk 64 Maple 47 Mortar no Mud 102 Marble, Italian 169 Marble, Vermont 165 Mahogany 66 Oak, Canadian 54 Oak. live, seasoned 67 Oak, white, dry 54 Oil, linseed 59 Pine, yellow 34 Pine, white 34 Pine, red 37 Pin e, well seasoned 30 Platina 1,219 Red Hickory 52 Silver 625^4' Steel, plates 487X Steel, soft 4S9 Stone, common, about 358 Sand, wet, about 128 Spruce 31 Tm 455 Tar 63 Vinegar 67 Water, salt 64 Water, rain " 62 Willov 36 Zinc, cast 428 Rule for safety valves. To find the distance, ball should be placed on lever, when the weight is known, or the distance is known and the weight is not known. Multiply the pressure required by area of valve, multiply the pressure required by area of valve, multiply the an- swer by the fulcrum; subtract the weight of the lever, valve and stem, and divide by the weight of ball for di.s- tance, or divide by distance for weig^ht of ball with the same example as follows: 8i Weight of ball, Pressure, Wt. of L. V. & steam, Fulcrum, Area of valve, EXAMPLE: 60 lbs. 100 " 100 lbs. pressure, 3 area of valve. 30 •• 4 inch, 300 4 fulcrum. 1200 30 wt. of L. V. & St. 60)1170 ig}4 inch ball should be hung on lever. The mean effective weight of valve, lever, and stem is found by connecting the lever at fulcrum, tie the valve- stem to lever with a string, attach a spring scale to lever immediately over valve, and raise until the valve is clear of its seat which will give the mean effective weight of lever, valve and stem. Rui^E for figuring the safety valve and to know the pressure when the area of valve, the weight of lever, valve and stem, the distance the fulcrum is from valve, and weight of ball is known. Divide fulcrum into length of lever, multiply answer by weight of ball, add weight of lever, valve and stem, divide by area of valve. Answer will be steam pressure. Weight of ball, 50 lbs. 2 . 25 Wt. of L. V. & stem, 30 lbs. 2 . 25 Fulcrum, 4 in. 5.0625 2}^ in. .7854 20 in. 3.97608750 area. 4)20 5 JO 250 30 Diam. of valve, Length of lever, Add as many ciphers to the dividend as 3.9 )280.0 there are decimals in the divisor, and lbs. press. 71. |{^ divide as whole numbers. (3 ^ .'82 *Co measure or mark off the lever, you measure the ful- cnmi and make notches the same distance as fulcrum; if fulcrum is 4 inches, each notch must be 4 inches apart. Ques. What is meant by a fulcrum ? Ans. The dis- tance valve stem is from where the lever is connected. SCREW CUTTrNG LATHE- FOR CUTTING ANY SIZ:^ THREAD. POINTS FOR MACHINISTS. RuivB TO Gear a Lathe for Screw-Cutting.— Every screw cutting lathe contains a long screw called the lead screw, which feeds the carriage of the lathe while cutting screws; upon the end of this screw is placed a gear to which is transmitted motion from another gear placed on the end of the spindle; these gears each contain a different number of teeth, for the purpose of cutting different threads, and the threads are cut a certain number to the inch, varying from one to fifty. Therefore, to find the proper gears to cut a certain num- ber of threads to the inch, you will first multiply the number of threads you desire to cut to the inch by any small number, 4 for instance, and this ^nll give you the proper gear to put on the lead screw. Then with the same number, 4, multiply the number of threads to the inch in the lead screw, and this will give you the proper gear to put on the spindle. For example, if you want to cut 12 to the inch, multiply 12 by 4, and it will give you 48. Put this gear on the lead screw, theu with the same number 4, multiply the number of threads to the inch in the lead screw. If it is 5, for instance, it will give you 20; put this on the spindle and your lathe is geared. It the lead screw is 4, 5, 6, 7 or 8, the same rule holds good. Always multiply the number of threads to be cut first. Some — indeed, most small lathes — are now made with a stud geared into the spindle, which stud only runs half as fast as the spindle, and in finding the gears for these latlies you will first multiply the number of threads to be cut, as before, and then multiply the number of threads on the lead screw as double the numbsr it is. For in- stance, if you want to cut 10 to the inch, multiply by 4, and you get 40; put this on the lead screw, then, if your lead screw is 5 to the inch, you call it 10, and multiply by 4, and it will give you 40. Put this on your stud and your lathe is geared, ready for cutting. Ruild it over the fire until the oil burns off; then put the spring in the oil again, then in the fire; do this three times; after the last time plunge it into water and cool off. The United States Government Tempering Secret and durability to the poorest kind of steel. Siegfried's specification reads as follows: "first heat the steel to a cherry red, in a clean smith's fire, and then cover the steel with common salt, purifying the fire also by throwing in salt. Work the steel in this condition, and while subjected to this treatment, iintil it is brought into nearly its finished form. Then substitute for the «alt a compound composed of the following ingredients 87 and in about the following proportions: One part by weight of each of the following substances; salt, sul- phate of copper, sal-ammoniac and sal-soda, together with Yz part by weight of pure saltpeter, said ingre- dients being pulverized and mixed; alternately lieat the steel and treat it by covering with this mixture and ham- mering it until it is thoroughly refined and brought into its finished form. Then return it to the fire and heat it slowly to a cherry red, and then plunge it into a bath composed of the following ingredients, in substantially the following proportions for the required quantity: of rain water, i gal.; alum, sal-soda, sulphate of copper, of each i)^ ozs; saltpeter, i oz., and of salt, 6 ozs. These quantities and proportions are stated as being practically the best, but it is manifest that they may be slightly changed without departing from the principles of my invention." DIRECTIONS FOR JOINING BANDSAWS The following directions for joining band saws are given by the Denance Machine Works: Bevel each end of saw the length of two teeth. Make a good joint. Fasten the saw in brazing clamps with the backs against the shoulder, and W2t the joint with solder- water, or with a creamy mixture made b}^ rubbing a lump of borax in about a teaspooaful of water on a slate. Put in the joint a piece of silver solder the full size thereof, and clamp with tongs heated to a light red (not white) heat. As soon as the solder fuses blacken the tong'^ with water and take them ofif. Remove the saw, hammer it if necessary, and file down to an even thickness, finishing by draw-filing lengthwise. S8 THE CORLISS ENGINE. ADJUSTMENT AND SETTING OF THE CORLISS ENGINE VALVES. It often happens that engineers, under whose control Corliss engines are placed, are not practically acquainted with the operation of the Corliss valve gear, and are at a loss what to do should the gear need adjustment. By carefully observing the following quesdons and answers, the desired information will be found. Ques. Into how many classes are the different types of Corliss valve gear divided ? Ans. Into two general classes. Ques. Which are they? Ans. To the first class belong the crab-claw gear. To the second class belong the half-moon valve gear. Ques. Which is the more favorable and widely known type now in general use ? Ans. The half-moon type. Ques. Why so? Ans. Because the old style crab- claw steam valve opens toward the center of the cylinder, which obstructs the supply passage and forces the steam 89 to pass over and around the valves. This fault is over- come in the half moon type, as the steam valve opens away from the center of the cylinder, thus leaving a clear and direct passage for the steam into the cylinder. Ques. Do the two different styles make any difference into the opening of the exhaust valves? Ans. No. The difference in the *-.wo classes is simply in the direc- tion of movement of steam valves; the exhaust valves open the same in either class, viz. : away from the center of the cylinder. Ques. What name has the Corliss valve gear? Ans. It is called a detachable valve gear. Ques. Why is it called detachable ? Ans. Because the steam valves open positively at the proper time by the direct action of the working parts of the engine, and continue to open until the connection with the working parts of the engine are broken by detaching or tripping the hook, by action of the cut-off cams. Ques. How are the steam valves closed ? Ans. When Jie steam valves are detached they are closed by the action of springs, weights, or more generally vacuum dash pots, thus cutting off the supply of steam. Ques. How is the detachment or tripping deter- mined? Ans. The time in the stroke at which the trip- ping takes place is known by the position of the cut off cams, which are moved and controlled by the governor. Ques. Does the cut-off cams trip the hook always at the same point ? Ans. No. The cut-off is determinea by the requirements of the load on the engine. Ques. By what name is this cut-off known? Ans The automatic cut-off. Ques. How is the theory of the Corliss valve motioa easily understood ? Ans. The theory is easily under- 90 stood by considering the four valves as the four parts (or edges) of a common slide valve. Ques. Why are the four valves of the Corliss engine considered as the four parts (or edges) of the common slide valve ? Ans. The working edges of th'^ two steam valves answering as the two steam edges of the slide valve, and the working edges of the two exhaust valves as the exhaust edges of the slide valve. Ques. The Corliss having four valves, and the com- mon slide valve only one, does it not make any difference in setting ? Ans. As far as the setting the principle is the same; the only difference is in the adjustment. Ques. Why does the adjustment make a difference? Ans. The four working edges of the common slide valve -are in one solid valve, so that any change or adjustment of one of the edges interferes with the other three. If one edge is to be changed in reference to the others, it must be done by altering the valve itself The Corliss valves, on the other hand, are adjustable, each by itself, and any one of the valves may be changed without dis- turbing the other three. Ques. Can the adjustment be made while running ? Ans, When the engineer is familiar with his engine and knows what changes are necessary, the adjustment may be, and is frequently made without stopping the engine. Ques. How many edges has a slide valve? Ans. Four — two steam and two exhaust. Ques. Have the Corliss valves the same number of edges? Ans. No. Each Corlisss valve represents an edge of the common slide valve, viz. : two steam edges, two steam valves, two exhaust edges, two exhaust valves. Ques. How are the valves connected to the eccentric and worked on the Corliss engines? Ans. With the wrist-plate, carrier arm, rocker arm, and reach rod. 9^ Ques. Is the wrist-plate good for any other purpose ? Ans. Yes. It modifies the speed of travel at different parts of the stroke, in relation to each other, and gives a quick and constantly increasing speed when opening the steam valves, and a quick opening and closing of the exhaust valves. Ques. When do the steam and exhaust valves travel slowest ? Ans. When they are closed. Ones. Can the valves of Corliss engines be adjusted when the reach rod is unhooked from the wrist-plate, so the valves may be properly set, independent of the posi- tion of the crank ? Ans. Yes. Ques. Are the Corliss valves easily set ? Ans. If the engineer has any knowledge, as he should have, of the ordinary slide valve, and of the effect of "lap and lead," as applied to its workings, and will consider the Corliss valve gear in the light of this knowledge, he will soon master the seeming difficulties in his way and find the Corliss gear to be the simplest, most perfect and most easily adjusted of all valve motions. Ques. How would you go about setting the Corliss valves? Ans. Begin by taking off the black caps or black heads of all four valve chambers. Guide lines will be found on the ends of the valves and on the ends of the chambers, as foUow^s: On the steam valves, coincid- ing with the working edges of the valves; on the steam valve chamber, coinciding with the working edges of the steam ports. On the exhaust valves and ports, guide lines are also scribed to set them b}-. The wrist-plate is centrally between the four valve chambers on the valve gear side of the cylinder. A well defined line will be found on the stand which is bolted to the cylinder, and three lines on the hub of the wrist-plate, which, when they conicide with the line on the stand, show the central 92 position of the wrist-plale and the extremes of its throw or travel. To adjust the valves, first unhook the reach rod connecting wrist-plate with rocker arm and place and hold the wrist-plate in its central position. The connecting rods between steam and exhaust valve arms and wrist-plate are made with right and left hand screw threads on their opposite ends, and provided with jamb nuts, so that by slacking the jamb nuts and turning the rod they can be lengthened or shortened as desired. By means of this adjustment, set the steam valves so that they will have % inch lap for lo inch diameter of cylin- der, and % inch lap for 32 inch diameter of cylinder, and for intermediate diameters in proportion. For the exhaust, set them with 1-16 inch lap for 10 inch bore, and I inch lap for 32 inch bore on non-con- densing engines and nearly double this amount on con- densing engines, for good results. Lap on the steam and exhaust valves will be shown by the lines on the valves being nearer the center of the cylinder than the lines on the valve chambers. Having made this adjust- ment of the valves, the rods connecting the steam valve arms with the dash pots should be adjusted by turning the wrist plate to its extremes of travel and adjusting the rod so that when it is down as far as it will go, the sq. steel block on the valve arm will just clear the shoulder on the hook. If the rod is left too long, the steam valve stem will be likely to be either bent or broken; if too short, the hook will not engage, and consequently the valve will not open. Having adjusted the valves as stated, hook the engine in and with the eccentric loose on the shaft, turn it over and adjust the eccentric rod so that the wrist-plate will have the correct extremes of travel, as indicated by the lines on back of hub of wrist- plate. Then place the crank on either dead center and 93 turn the eccentric in the direction in which the engine 5s to run to show an opening at the steam valve of from ^ to I inch, depending upon the speed the engine is to run. This opening will be shown by the line on the valve being nearer the end of the cylinder than the line on the valve chamber. This opening gives the "lead" or port opening when the engine is on the dead center. The faster the engine is to run the more lead it requires, as a general rule. Having turned the eccentric so as to secure the desired amount of lead, tighten it securely, by means of the set screw, and turn the engine over to the other center, and note if the other steam valve has the same lead. If not, adjust by lengthening or shortening the connecting rod to the wrist-plate as the case may be necessary to do. If the engine has the half-moon, crab-claw, or other gear which opens the valves toward the center of the cyl- inder, the manner fo the adjustment will be the same, ex- cept that the "lap" on the steam valves will be shown when the line on the steam valve is nearer the end of the cylinder, and the "lead" when this Une is nearer the center of the cylinder than the line on the valve chamber. The adjustment of the exhaust valves and the amount of "lap" and "lead" will be the same in either case. . To adjust the rods connecting the cut-off or tripping cams with the governor, have the governor at rest, and the wrist-plate at one extreme of its travel. Then adjust the rod connecting with the cut-off cam on the opposite steam valve so that the cams will clear the steel on the tail of the hook about ^\ inch. Turn the wrist-plate to the opposite extreme of travel and adjust. the cam for the other valve in the same manner. To equalize the cut-off and test its correctness, hook th" engine in and block the governor up about iX inch, which will bring it io its 94 average position when running. Then turn the engine slowly, in the direction in which it is to run, and note the distance the cross-h-^ad has traveled from its extreme position at dead center when the cut-off cam trips or de- taches the steam valve. Continue to turn the engine be- yond the other dead center and note the distance of cross-heads from its extreme of travel when the valve drops. If the distance is the same as when the other valve drojped the cut-off is equal. If not, adjust either one or the other of the rods until the distances are the same. By following these directions the engine will do good work, but to know just what it is doing the engineer should use the indicator often. No engine room is com- plete without a good indicator, and no engineer can be well posted as to what his engine is doing and keep it in its best possible condition for good work without having an indicator and using it often. THE DYNAIVIO. Ques. What is a Dynamo? Ans. A Dynamo is a machine in which Electricity is gathered and forced out through wires for lighting, electro-painting, etc. Ques. What does a Dynamo consist of? Ans. A Dynamo consists of a field, frame, armature, commutator, brushes, brush holders, pins for the brush holder, and a quadrant. Ques. What is meant by a field? Ans. It means the magnets connected to the frame with bolts. Ques. What are magnets? Ans. Magnets are iron cores, wound with insulated wire. These magnets are called electro-magnets because they become magnetic only when a current passes through the wire. 95 C. & C. DYNAMO. McDOUGALL & CUMMINGS, Chicago. 9b Ques. How is the current generated? Ans. By the rotary motion of the armature between the poles of the magnet. Ques. What does an armature consist of? Ans. It consists of a steel or iron shaft, around which' insulated wire is wound, the shaft having a 6 or 8 inch bearing at each end. Ques. How is this current conducted to the lamps ? Ans. By means of brushes made out of copper strips of wires about 6 or 8 inches long, soldered together at one end and held on the commutator by means of brush hold- ers made out of brass. These holders are on long pins, the pins are nutted to a quadrant and the quadrant is fastened to a frame. Ques. How many brushes are there generally, and where are they ? Ans, There are 2 and 4 brushes, two on one side of the commutator and two directly opposite, according to size of machine. Ques. What is a commutator ? Ans. A commutator is made out of segments of copper and segments of insu- lation. Ques. Can a commutator be taken off when worn out ? Ans. Yes. Ques. How is it generally done ? Ans. By taking out the brushes, brush holders, the pins and the armature from the dynamo, then place the two ends of the shaft on wooden horses, mark the wires connecting the arma- ture and commutator by attaching numbered tags (so as to place them, when the new commutator is put on) then disconnect the wires between the commutator and arma- ture and take off the commutator from the shaft. Ques. How should a dynamo be looked after and run ? Ans. See that the machine is clean, journals cool, and that the proper speed is kept up; see that the brushes are 97 directly opposite each other and that the quadrant and brushes are moved around on the commutator according to the number of lights in use. Ques. How would you know when to move the quad- rant? Ans. By the sparking of the brushes on the commutator. Ques. What mainly causes the dynamo to flash or spark ? Ans. The brushes not being directly opposite through the diameter of the commutator, sometimes not enough pressure on the commutator, sometimes the brushes not far enough around on the commutator, also too much brush surface. Sparking at the brushes. Some styles of dynamos will spark at the brushes in spite of anything the atten- dant can do to prevent it, but many other styles of dyn- amos can be run with absolutely no sparks on the commutator. The first point to be attended to is to get your commutator perfectly smooth, or as near it as possible, with the means at your cormnand, for if the commutator is not true you can not prevent it from sparking. If you have a slide-rest, use it, and get your commuta- tor round and true from end to end. If you have no slide-rest, a i6 in. bastard file will do nearly as well. Take th^ brushes and brush holders c»£f, so that you may have plenty of room to work. Start the dynamo to turn- ing very slowly. Hold a piece of chalk so near the com- mutator that it will mark all of the high spots. Move the chalk slowly from end to end of the commutator, so that all high places on the full length will be chalked. Stop the dynamo and amuse yourself filing off those parts that have been marked by the chalk. If you have no- ticed while the dynamo was turning about how much the commutator was "'out," you can easily tell about how 98 much you will have to file away to bring it true. Hie ofi all the places that have been marked, and then start up again slowly, and chalk it a^ain. Repeat the chalking and filing until the commutator is round, and of the same size from end to end. Next get a piece o*^ shingle, thin board, or a piece of lathe even will do, and wrap a sheet of No. oo. sand-paper around it — never use emery paper or cloth — start the dynamo at a pretty lively speed, and smooth the commut- ator down with the sand-paper, holding the flat side against the work. It is not necessary to work it down to a polished surface, although it would be well if it were polished. Now that you have your commutator round and smooth — and it must be so sm )Oth that there are none of the marks left on the c )mmutdtor, for it was trouble that caused tnem and if any be left they will certainly cause more trouble. Now that you know your commutator is in good shape, proceed to set your brushes, being certiin that the points of opposite brushes art directly opposite through the diameter. The pressure put on the brushes need only be just sufficient to vc^^\& good contact. It is not necessary to have much pressure to preserve good contact. Should the contact be too slight it will make itself known by a peculiar noise that is indescribable, being neither a snap, crack, or pop, and yet might be calle 1 by either of these names You may be sure that the noise will call your at- tention if you are anywhere near, and after you have once noticed it you will easily recognize it the next time. This noise and considerable sparking will always be pres- ent when the brushes do not press heavily enough upon the commutator. If the brushes are not set with the points directly op- posite, sparking will result. 99 If tlie brushes are set ahead of the neutral line or ba<^ of it they will spark. When setting four brushes on a commutator that re- quires two brushes side by side, it is sometimes difficult to get all four of them of an equal length, or evenly divided on the commutator, one or more of them will spark more or less. After rocking the orushes back and forth a trifle to find the point of least sparking, you can then tell by the color of the spark whether the brush should be lengthened or shortened. When the spark is of a decided- ly greenish color the brush is too short, but if the spark appears to spatter and shows a reddish hue, then you will find that the brush is too long, or it is so worn, that there is too much of it in contact. By the way, you will find full}^ as much, if not more, trouble arising from having too much brush in contact, than f-om having too little. Cutting of Commutator, scratching and eating away of the segments, is mostly due to the brushes having too much surface in contact, and increase of pressure vaW wear away the commutator, and having too much of the face of the brush in contact will cause -in edge of the seg- ments to become eaten away, and if not attended to, they will, in a very short time, become as rough and uneven as a corduroy road. With the thicker style of brushes we have never found it necessary, even when running at full load, to have more than one-third of the full end surface of the brush in contact with the commutator, and further, we have found that if we allowed the brush to become so worn that even one-half of the end surface bore on the seg- ments it would cause sparking. To prevent filing the brushes every day (which would be wasteful,) to keep them in the best of order, we found that they could, with great advantage, be turned thf other side up and allowed to wear in that way until the surface became to great. This resulted in getting more than twice the amount of work out of a brush than was possible by filing always from one side, or trimming the ends S(j[nare as often as they became badly worn. If the iiiilllijiiiulim|ii!:|:i;iiliiniiini!jjili|jjilli: THE EDISON DYNAMO. commutator becomes very hot you will be quite sme tc find that your brushes are badly worn. Flat Spots on the commutator, frequently explained by laying it to sot spots in the copper, we have always found to result from an entirely different cause. When the marks ha ,'e the appearance of a blow from the pene of a hammer, it will generalh^ be found to be caused by a loosely connected or badly soldered armatuie wire con- nection. A spot of this kind continue to grow larger until the cause of it is removed and the commutator dressed down smooth. At the end of the segments a spark or scream of fire en- circling the whole commutator will sometimes be noticed. This may be caused by an accumulation of oil or cop- per-dust or dirt, that causes a short circuit, but it will generally be found that the insulation is charred or burned through at some place near where the spark is noticed, and if a careful examination of the armature wires are made you will find that a connection is loose or has very poor conductivity. Allowing the commutator to run hot wnll increase difiiculties of this kind. THE PRINCIPAL OF^ THE DYNAMOCOM- PARED WITH THE STEAM PUMP. We are often asked how can a dynamo be easily under- stood; the question coming from engineers who have charge of electric lighting plants. The whole thing may be compared, in its principles, to the working of a steam pump forcing 'water through a line of pipe of the same extent as the line wires. The dynamo (or pump) forces electricity instead of water. So long as the dynamo or pump works continuously the pipes or wires are filled with a current of water or elec- tricity, flowing in one direction; in other words, a con- tinuous current. Thus we may say: that a certain number of pounds steam pressure is required to overcome the friction of the water in the pipes, so that so many cubic feet or gallons of water shall be delivered per minute, I02 equally true we can say, so many volts are required to overcome the resistance of the wire, so that the current shall be delivered in so many amperes per minute. Hence, to simplify, we may say pounds of steam pressure = volts; the friction=resistance; the pipe=the wire; cur- rent = volume of water in motion, and amperes of elec- tricity =gallons of water delivered at the end per minute. Every engineer knows that the larger the pipe the more gallons water per minute, and the less relative friction, so the larger the wire the more current can be carried and the less resistance, relative to the number amperes deliv- ered. The same analogy holds good in the opposite, for the smaller the pipe or wire, the greater the friction or re- sistance. Every engineer who uses a steam pump or an injector, knows that there is some point to which, if his pipes were reduced in size, nearly or quite all his power (steam pressure) would be absorbed in friction. So elec- trically, our voltage may be largely consumed or absorbed by too small a wire; in either case — either the water or the electiicity — the result of the work done is in both cases uniform and identical, viz: A continuous current, and is the current that has been generally used for the production of ligljt and power. The other current, which is largely employed in the generation of electrical power, viz: the alternating current, differs essentially from that which we have described above, and in fact our analogy to the working of a pump comes to an end. The current from an alternating dynamo, instead of flowing contin- uously and directly, is simply a vibratory movement, or a "back and forth flow." Here the supremacy of elec- tricity as a power, or rather as a transmittor of power, comes in, for, returning to one pump, should we at each alternate stroke of the pump reverse the direction of flow of the water, the entire power, or nearly all of it, would I03 be absorbed by its weight, and the friction in the pipes. But electricity boring without weight, there is of course no loss by reversing its flow; indeed, the possibilities of application to useful service, dependent on tue reversals, are of greatest value. To clearly explain the action of the alternating system, we have to consider the requirements under which electricity does the most acceptable work. Every engineer who is making electric lights knows that the most satisfactory results, i. e., the best light is obtained by using a dynamo and distributing system of as high voltage as possible, in conjunction with a lamp of low vol- tage. Here, then, we have two actually opposite condi- tions, which must be harmonized to produce a perfect result in their action, and which are plainly impossible in the continuous current system, which we have explained by the comparison to our pump; because it is evident, to renew the comparison; that, if we are carrying a pressure (steam), and our line of pipes is calculated to deliver a certain amount of water per minute; if we throttle down at the delivery end, so as to deliver only ^ or 3^5 of the amount, we shall only be able to do so by reducing our pressure relatively, involving a great loss of ef&ciency, or incur the risk of destruction to the plant at some point. Hence we are obliged to provide some appliance which shall intervene to convert the high voltage of the dynamo and circuit to the low voltage of the lamps. When such an appliance is used it is known as a converter system, and the use of an alternating current and converter sys- tem are mutually dependent on and necessary to each other. This system can be compared to the engineer's system of steam heating in his building thus: Suppose he carries 75 lbs. boiler pressure, and the steam is carried into the building in one main pipe, and from that is distributed I04 by risers, etc., to the different radiators in the building. It is evident that he has no use for full boiler pressure on the risers and radiators, as, even if they would stand it for a time, it would be no more effective for heating than a reduced pressure; hence, he puts in a reducing valve in the steam main, between the boilers and risers. So, then, the converter used in connection with an al- ternating current is exactly an electrical reducing valve, with a high pressure (voltage) on one side, and a low working pressure (voltage) on the other. Thus, by us- ing this converter he may carry any voltage at the dy- namo and primary circuit, reducing into the secondary to conform to the amount of current required. Each cur- rent continuous or alternate, have especial fields to which they are adapted, and while both are extensively in use each has its peculiar adaption. Ques. How do you understand the term "volt"? Ans. The "volt" is a measure of electro — motive force, or original energy. Corresponding to the dynamic term "pressure," but not of power." It is based on the product of one Daniell cell of a battery. Ques. How do you understand the term "ohm" ? Ans. The "ohm" is the measure of resistance, and com- pares to the dynamic term of "loss by transmission." It is based on the resistence offered by a copper wire .05 in. diameter, 250 ft. long; or a copper wire, 32 guage, 10 ft. long. Ques. How do you understand the term "ampere"? Ans. The "ampere," is the measure for current or what passes; the intensity, it may be called, and is comparable to the dynamic term of "power transmitted," or "effect." It is the residual force of one "volt" after passing through one "ohm" of resistance. 105 Ques. How do you understand the term '*coulomb"? Ans. The "coulomb" is a measure of current, qualified by time; one ampere acting for one second of time, com- paring in nature with the dynamic "foot-pound." Ques. How do you understand the term "watt"? Ans. The "watt" is the unit for dynamic effect produced by electro-motive force or current. It equals 44.22 foot- pounds, or 746 h. p. Ques. How many "coulombs" in a "watt"? Ans. There are 44.22 "coulombs." Ques. How many "watts" in an electrical h. p.? Ans. There are 746 "watts" in a h. p. Ques, How many horse power will it take to run a 50 arc light dynamo. Bach arc light equaling 45 ' 'volts' ' and 8 "amperes" giving 1600 candle power to each light? Ans. Multiply the "voltage" by the "amperes" then the number of lights lit, and divide by electrical h. p. which is 746 "watts." The answer will be the h. p. of engine required. FORCE OF A THUNDERBOLT. It has been calculated that the electromotive force of a bolt of lightning is about 3,500,000 volts, the current about 14,000,000 amperes, and the time to be one-twenty- thousandth part of a second. In such a bolt there is an energy of 2,450,000,000 watts, or 3,284, 182 horse-power. PROTECTING BUILDINGS. There is a popular saying or proverb, that "lightning never strikes twice in the same place, ' ' and the casualties that occur from it are so much more rare than those that happen from other causes that a man who takes no pre- cautions to guard against such is not considered negligent lo6 by any except those interested in "protecting" his prop- erty against damage by lightning. As a matter of fact, the lightning rod pedler has come to be a standard sub- ject of newspaper jokes and considered a sort of harmless fraud by the public. He is bound to meet with some success, however, in his business, because the subject of atmospheric electricity, and thunderstorms is so little understood even by scientists. It is not at all probable that thunder storms and light- ning discharges of the present day differ in the least from those of a hundred or a thousand years ago, but it is very apparent that a greater loss of life and property occurs from them now than ever before, a fact easily ac- counted for by the increase of p( pulation and of property liable to such damage. The enormous increase in the number of newspapers and of facilities for collecting and distributing such items of news naturally also tend to make the impression that such casualties occur oftener than of yore. However infrequent such accidents occur we know that they do happen sometimes and always un- expectedly and very suddenly. It is, therefore, the port of wisdom and prudence to take such precautions as science and experience teach against these contingencies. THK CAUSE OF THUNDERSTORMS. It is generally conceded that the evaporation cf water from the surface of the earth, most of which contains some kind of mineral salt in solution, is the primary ori- rin of most of the phenomena of atmospheric electric- ity, and those who do not fully indorse this theory admit that it is the great agency for stirring up the potential energy derived from txie sun and distributing it over the universe, whether in thunderstorms or in the incessant quiet changes that are going qn in the various forms of 107 forces employed by nature. Vapor, whether invisible in the ultimate divisibility of its component storms or in a partially condensed condition in the form of clouds, is the vehicle in which is stored the sun's potential energy which we call electricity. Hence the common concep- tion of lightning is that it is an electric fluid packed away in the clouds which may at uncertain times be dis- charged to the earth with destructive energy in the form of "thunder bolts." The lightning rod, or conductor, as the electrians call it, is regarded as having some sort of power to attract these thunder bolts and convey them to the ground like a pipe would carry water. These popu- lar ideas were derived mostly from the eloquent lightning rod pedler and are not only erroneous but lead to mis- takes in the location and setting up of lightning rods that sometimes cause fatal results. Atmospheric electricity is just the same as that we use for motive power, heat and light. The thunder cloud is, to all intents, a condenser plate upon which terminates the polarized chain of a cir- cuit, and its action will depend upon the nature of the opposite condensing plate. If this is another cloud at a distance the discharge will take place between them and have little effect upon the earth, except what is called "induction," that will effect telephone, telegraph, and other wires carrying currents of low potential, and people of a peculiar nervous organization. If, however, the earth forms the opposite condensing plate, which often happens, then the discharge will be from the clouds to the earth and sometimes in the opposite direction. In the latter case all bodies, as well as the air between the clouds and the earth are "polarized" and the discharges always occur in the line of least resistance when the tension rises to a degree greater than the resist- ance of the circuit can sustain. These discharges are io8 very erratic and very slight circumstances will determine their direction, such as a tree, a man, or an animal stand- ing on moist ground, a vein of mineral, a line of piping in the ground, etc., etc. This brief and crude effort to portray the nature of a discharge of lightning will convey some idea of the prin- ciples of lightning rods to avoid the effect. They are not intended to attract or to convey a discharge of lightning from the clouds to the ground but to supercede the con- dition of polarization and tension in the space to be pn*- tected, and if properly made and put up wdll diminish the likelihood and frequency of the discharges, but it is undoubtedly true that they also invite them by setting up a line of low resistance. The theory of the lightning rod is that it practically raises the earth's surface to a height that corresponds with the electric relations of the rod and the air, and the protected area is a cone whose base equals the height of the rod, but this theory applies to the rod itself and is greatly affected by the nature of the buildings in the pro- tected area, their form, material and contents. Just what form this protected area assumes when there are build- ings within it or to what points it extends no one has ever yet discovered. But whatever the space protected may be, within it the rod (or conductor) lowers the con- dition of tension, and either nullifies it or transferes it to the space outside of the protected area. When a charged cloud approaches and sets up an * 'inductive circuit" to the earth the rod conducts the current quietly to the earth and thus lowers the potential above it so that frequently it does not accumulate sufficiently to cause a discharge — that is a lightning flash. And this is the real purpose of lightning rods. log In putting up lightning rods the object should ; be to connect with earth every portion of the building, and as, in practice this is impossible with any but metal build- ings, they should connect every exposed point and par- ticular care should be taken with the chimneys and smoke stacks. Every chimney lined with soot is a fine con- ductor of electricity, and if there is a fire in it the warm air ascending to the clouds invites a discharge. Nine buildings out of every ten struck by lightning receive the discharge by the chimneys. Every piece of metal in the construction of the building should be connected with the conductors. For small buildings iron rods are used. If a large number are used and all properly connected to earth % inch galvanized telegraph wire will answer every pur- pose but for a single conductor not less than half inch rod should be used ; solid rod is best for it is the mass or weight of metal that conducts and not its surface and a solid rod presents the least surface to rust. Screw or riveted joints will not do. The rods must have continu- ous metalic connections. The most important thing in the whole matter of pro- tecting houses from lightning is the earth connections. Every rod must be connected to water or to earth that is saturated with moisture. Water and gas mains are the best connections provided a good metallic connection is made. A well constantly supplied by a stream affords a good earth connection, but the earth connection is suflScient. no PRACTICAL POINTS FOR ENGINEERS. Steam-pipes, whether for power or for heating, should always pitch downward from the boiler, that the con- densed water, etc., may have the same direction as the .steam, or otherwise there will be trouble, unless the pipes are either very short or very large. Globe valves should always be so placed in steam -pipes that their stems are very nearly horizontal, in order to prevent a heavy accumulation of condensed water in the pipes. Wherever a horizontal steam-pipe is reduced in size there should be a drip to avoid filling the. "larger pipe partially with condensed water. In order to make a rust joint that will stand heat and cold as well as rough usage, mix ten (lo) parts of iron filings and three (3) parts of chloride of lime with enough water to make a paste. Put the mixture on the joint and bolt firmly; in twelve hours it will be set so that the iron will break sooner than the cement. . TO REIMOVE RUST FROM STEEI.. Cover the steel for a couple of days with sweet oil; then with finely powdered unslacked lime (known as quick lime,) rub the steel until the rust is removed; then re-oil to prevent further rust. HOW TO CLEAN BRASS. Nitric acid, one part; sulphuric acid yi part. Mix in a jar, swab on and rub with sawdust. HOW TO CLEAN DIRTY BRASS QUICKLY. Finely rubbed bichromate of potassa, mixed with twice its bulk of sulphuric acid and an equal quantity of water will clean the dirtiest brass very quickly. Ill A soft alloy which attaches itself so firmly to tha sur- face of metals, glass and porcelain that it can be em- ployed to solder articles that will not bear a very high temperature, can be made as follows: Copper dust ob- tained by precipitation from a solution of the sulphate b}' means of zinc is put in a cast iron or porcelain lined mortar and mixed with strong sulphuric acid, specific gravity 1.85. From 20 to 30 or 36 parts of the copper are taken, according to the hardness desired. To the cake formed of acid and copper there ia added, under constant stirring, 70 parts of mercury. When well mixed the amalgum is carefully rinsed with warm water to remove all the acid, and then set aside to cool. In ten or twelve hours it is hard enough to scratch tin. If it is to be used now, it is to be heated so hot that when worked over and brayed in an iron mortar it becomes as soft as wax. In this ductile form it can be spread out on any surface, to which it adheres with great tenacity when it gets cold and hard. Cement for smali^ Leaks in Steam Boilers. Experiments have shown the following to be effectual for stopping small leaks from the seams of boilers, pipes, etc. Mix equal parts of air-slacked lime and fine sand; and finely powdered litherage in parts equal to both the lime and sand. Keep the powder dry in a botile or covered box. When wanted to apply, mix as much as needed to a paste, with boiled linseed oil, and apply quickly, as it soon hardens. Cement for Iron Works. It is sometimes advisable to fix two pieces of iron, as pipes for water or steam, firmly together as a permanency. Sal-ammoniac, one part by weight; sulphur, two parts; fine iron borings free from oil. The three should be 113 made with water to a conveniently handled paste. The theory of its action is simply union by oxidation. To drive a nail in hard seasoned wood, dip the points in lard, and they can be driven home without difficulty. Sewing-machine Oii<. Best paraffine oil, i oz; best sperm oil, i oz. Mix and use. Cement wke That on Postage Stamps: Mix two ozs. of Mextrine, acetic acid, Yz oz., water, 2^ ozs. After mixture is made, add yi oz, alcohol. To Make Tracing Paper Wet common drawing paper or any other kind, with benzine, the paper becomes transparent immediately, and can be placed over a drawing or picture, to be trans- ferred by tracing with a pencil. This is very valuable. To Joint IvEad Pipes. Widen out the end of one pipe with a taper wood drift, and scrape it clean outside and inside; scrape the end of the other pipe outside a little tapered, pnd insert it in the former; then solder the joint with common lead solder by pouring it on with a small ladle and work the solder with a pad made out of 2 or 3 plies of greased bed-tick by holding it under the joint and smoothing it over by working it round making a ball joint, first rubbing a little grease on the scraped parts or joint to be made — thus making it strong. To PowsH Brass. When the brass is made smooth by turning or filing with a ver^" fine file, it may be rubbed with a smooth fine grain stone, or with charcoal and water When it is quite smooth and free from scratches, it may be polished rotten stone and oil, alcohol, or spirits of turpentine. U3 To Fii^i^ Hoi^ES IN Castings. Lead, 9 parts; antimony, 2 parts; and bismuth, i part; this is melted and poured in to fill the holes. To Soften Iron or Steei. Anoint it all over with tallow; heat it in a charcoal fire; then let it cool. To Distinguish Wrought and Cast Iron FROM Steei.. File and polish the surfaces, and apply a drop of nitric acid, which is allowed to remain there for one or two minutes, and then washed off with water. The spot will then look a pale ashy gray on wrought iron, a brownish black on steel, a deep black on cast iron. The amoimt of carbon in iron or steel produces the different colors. To Case-harden Iron very deep. Put the iron to be case-hardened in a crucible with cyanide of potash, cover over and heat together, then plunge into water. This process will harden to the depth of three inches. To C1.EAN SteeI/.and Iron. Make i oz. soft soap and 2 oz. fine emery in a paste; rub it on the article with wash-leather and it will have a brilliant polish. How TO "FIGURE OUT" OF THE SCRAPE OF Ollr Daubed Sight-Feed Gi^asses. Hunt up a plumber friend, and get the use of his gaso- line "devil" for ten minutes. Plug one end of a glass tube; then heat about an inch in the middle; when hot, blow into the open end and the tube will quickly bulge itself. Cut off both ends to the right length, and. no more trouble will arise from oil-daubed glasses. 114 Look out for the oily waste, especially if there be any turpentine in it. Keep it in a fireproof receptacle, or better still, bum it up every night. Some dye-stuffs are as bad as oil. The total heat generated by an equai amount of oxidization is identical, whether it proceeds at so slow a rate as to show its effect only in the change of appearance of the article, or so rapidly that the temperature is high enough to consume the substance and ignite the fabric. A good composition for welding steel is made of one part of sil ammoniac ten parts borax. The ingredients should be poured together, fused until clear, poured out to cool and finally reduced to powder. To Find the Height of a Tree or Other Tai^i, Objects. Take two small sticks of even length, join them to- gether at "C" as shown in the following cut. Place the end "A""on a level with the eye, walk back to such a B I distance from the tree or object that the point "D" may be in a line with the root or base and the point "B'* in a line with the top or limb. The distance from the measurer's foot to the root or base of the tree or object, will be equal to the height of the limb or object. Ques. How can brass and other polished articles be kept from tarnishing? Ans, They can be covered with Its a thin coat of shellac dissolved in alcohol. The bright work should be warm before applying the coating so it will flow smoothly and dry quickly. Oues. Give a good recipe of cement that will fasten leather to metal or wood ? Ans. Mix a gill of best glue with little water, a teaspoonfull of glycerine, and use warm. Ques. Give a good black paint for boiler fronts ? Aus. Coal tar, ground graphite and turpentine is very durable. HOW TO RENOVATE BI^ACK GOODS. An excellent cleansing fluid, especially useful when men's garments require renovation, is prepared as fol- lows : Dissolve four ounces of white Castile soap shavings in a quart of boiling water. When cold add four ounces of ammonia, two ounces each of ether, alcohol, and gly- cerine, and a gallon of clear cold water. Mix thoroughly and as it will keep for a long time, bottle and cork tightly for future use. This mixture will cost about eighty cents, and will make eight quarts. For men's clothing, heavy cloth, etc., dilute a small quantity in an equal amount of water, and following the nap of the goods, sponge the stains with a piece of similar cloth. The grease that gathers upon the collars of coats will immediately disappear, and the undiluted fluid will vanquish the more obstinate spots. When clean, dry with another cloth, and dress the underside with a warm iron. This fluid is also useful when painted walls and wood-work require scouring, a cupful to a pail of warm water being the proper proportions. U6 RULE FCR CALCULATING SPEED AND SIZES OF PULLEYS. To tind the size of driving pulleys: Multij)ly the diameter of the driven by the number of revolutions it shall make, and divide the answer by the revolutions of the driver per minute. The answer will be the diameter of the driver. To find the diameter of the driven that shall make a given number of revolutions: Multiply the diameter of the driver by its number of revolutions, and divide the answer by the number of rev- olutions of the driven. The answer will be the diameter of the driven. To find the number of revolutions of the driven pulley: Multiply the diameter of the driver by its number of revolutions, and divide by the diameter of the driven. The answer will be the number of revolutions of the driven. HOW TO WRITE INSCRIPTIONS ON MBTAW. Take )4 lb. of nitric acid and i oz. of muriatic add, mix. shake well together, and it is ready for use. Cover the place you wish to mark with melted beeswax; when cold write your inscription plainly ij the wax clear to the metal with a sharp instrument; then apply the mixed acids with a feather, carefully filling each letter. Let it remain from i to lo minutes, according to appearance de- sired: then throw on water, which stops the process and removes the wax. RECIPE FOR NICKEL-PLATING WITHOUT A BATTERY. Take i}4 gills chloride of zinc, i gallon of clear water then add enough sulphate of nickel to turn it green, then heat it to a boil in a porcelain vessel. The heating makes 117 the solution cloudy, but does not injure it. Keep the so- lution next to boiling until the articles to be plated are done say from 30 to So minutes then when done polish with chalk first cooling the article in cold water. The articles to be plated should be very clean, to clean articles to be plated use nitric acid i part, sulphuric acid }4 part, put in stone jars, then drop in clear water. Strong lye can be used. All handling must be done with a copper wire. HOW TO PETRIFY WOOD. Gum salt, rock alum, white vinegar, chalk and peb- bles powder of each an equal qoantity. Mix well to- gether, if, after the ebulition is over, you throw into this liquid any wood or porus substance, it will petrify it.. RAILWAY SIGNALS. One whistle signifies "down brakes." Two whistles signify "off breaks." Three whistles signify "back up." Continued whistles signify "danger." Rapid short whistles "a cattle alarm." A sweeping parting of the hands on a level with the eyes, signifies "go ahead." Downward motion of the hands with extended arms, signifies "stop." Beckoning motion of one hand, signifies "back." Red flag waved up the track, signifies "danger." Red flag stuck up by the roadside, signifies "danger ahead. ' ' Red flag carried on a locomotive, signifies "an engine or train following. ' ' Red flag hoisted at a station is a signal to "stop." Lanterns at night raised and lowered vertically, is a sig- nal to "start." Lanterns swung across the track, means **stop." Lanterns swung in a circle to the left, signifies " back the train." Il8 TIME AND SPEED TABLE. 5 S CO S xo miles per hour is 6.00 5-00 4.00 3-20 3-00 2.43.5 • ... 2.30 2.24 2.08.5 2.00 M5.6 1.42.6 , 1.40 1.34-7 1.30 1.27.7 1.25.7 1. 21.7 1.18.2 1.15.0 1. 12.0 1.09.4 1.06.6 1.04,3 1.02.2 1.00.0 to 12 (1 ( 15 a < 18 a ( 20 (( ' ( 22 " ' 34 " * 25 << ( 28 i< < 30 ( 1 ( 34 (( 1 35 (. ( 36 (( ( 38 (( ( 40 (( ( 41 (< ( 42 (( ( 44 <( « 46 << ( 48 f water in a given time, multiply the number of cubic feet of water by 144 and divide the product by the area of the pipe in inches. To find the area of a required pipe the volume and vel- ocity of water being given, multiply the number of cubic feet of water by 144, and divide the product by the veloc- ity in feet per minute. The area being found, it is easy to get the diameter of the pipe necessary. The area of the steam piston, multiplied by the steam pressure, gives the total amount of pressure exerted. The area of the water piston, multiplied by the pressure of water per square inch gives the resistance. A margin must be made between the power and resistance, to move the pistons at the required speed; usually reckoned at about 50 per cent. How TO Prkserve Eggs. — To each pailful of water, add two pints of fresh slacked lime and one pint of com- mon salt; mix well. Fill your barrel half full with this fluid, put your eggs down in it any time after June, and they will keep two years if desired. To KiLIv AND GET RID OF BEDBUGS AND MOTHS. — Use either gasoline or benzine. In using these fluids be care- tvl about lights and fires as they are very inflammable. 121 Egg Stains. — To remove from spoons rub with chloride of sodium. Hair. — To clean hair, wash well with a mixture of soft water one pint; soda one ounce; cream tartar one-fourth ounce. Bites and Stings of Insects.— Wash with a solution of water of ammonia. Bite OF Cats. — Apply fat salt pork to the wound for a day or two, or until the poison is all extracted. Mad Dog Bites. — See a physician at once if possible, or apply caustic potash at once to the wound. Give enough whiskey to cause sleep. Ratti^esnake Bites.— Whiskey is supposed to be the great cure-all. Give enough to cause intoxication. Burns. — Make a paste of baking soda and water and apply it promptly to the bum. Will check the inflam- mation and pain. CcREW. —To remove an obdurate screw, apply a red hot iron to the head for a short time, the screw-driver being applied at once while the screw is hot. GivASS Stopper. — To remove a glass stopper from a bottle, warm the neck of the bottle with a warm iron, taking care not to warm the stopper This causes the bottle to expand and loosens the stopper. Fruit Stains. — To remove the stains of acid fruit from the hands, wash your ha ids in clear water, dry slightly, and 'while yet moist strike a match and hold your hands around the flame. The stains will disappear. Iron Rust. — ^To remove from muslin or white goods; thoroughly saturate the spots with lemon j uice and salt, and expose to the sun. Usually more than one applica- tion is required. A good way to prevent its appearance on clothes is when washing to always have them inclosed in a muslin bag when being boiled. To Stop Vomiting.— Drink freely of hot water, just as hot as can be borne. Hard Water. — ^To soften, boil it and expose to the atmosphere. Add a little soda. Medicine Stains. — To remove from spoons, rub with a rag dipped in sulphuric acid and wash off with soap suds. To Make A Smai