B. R. Wicks

The engine here described is especially designed for the benefit of the amateur who wishes to construct a simple working steam engine with his own tools.

This engine comes under a new name in the small engine field. It is called the ring frame, single acting, high speed, center crank steam engine, with piston valve and crank eceentric in place of the usual type of eccentric and eccentric strap. The crank eccentric and piston valve is used on this engine to avoid friction. Under this system the engine will be able to give from 1000 to 2000 r. p. m., and develop from 1-20 to 1/8 h. p. according to the boiler pressure used.

Model High Speed Engine 210

All the machine work to be done on the castings can be done in the lathe, as there is no planer work on the engine. A lathe that will swing four iuches and has a slide rest, will do the job. A few drills, reamers, taps and dies will have to be used, but very Jew.

The design and construction has been made as simple as possible. The drawings show the front and end sections. The various parts are lettered for clearness in distinguishing the parts to be used in the construction, one from the other. A is the cylinder, valve chest and frame cast in ore piece.

The machinery operations on the castings are as follows : The bottom is held in the vise and filed off true, then bolted to the lathe face plate, trued up by the outside of the casting and bored and reamed out to 7/8 in. standard. The 7/8 in bore must be a perfectly straight and smooth hole. When in position, face off the top of the cylinder.

The | hole for the valve chest is now to be drilled and reamed. Lay out the center of the valve chest 1 3-32 in. from the center of the cylinder and drill with a drill slightly under fin. and finish with a 3/8 in. reamer.

The 3/8 in. bore of the valve chest is tapped with a 7-16-32 V thread tap, 3-16 in. deep for the exhaust pipe bushing, and the bottom faced off with a small fly cutter on a 3/8 in. bar, so that the valve rod stuffing box P will set flush when in position.

The cylinder cover B is finished all over and can be done in a three jawed chuck to good advantage. A bolt circle must be made with a sharp pointed tool on the side that goes next to the cylinder. Lay out the circle in six equal parts. Notice the location of the cut out for the steam port. Drill the six holes with an N 28 drill.

The steam port is laid out, drilled and filed out to 3-32 in. wide and | in. long. The steam drill inlet boss is drilled and tapped with a 1-4-32 thread. Also drill two 5-32 holes in the bottom as shown in the drawings, for holding the frame A in position on bed M. The piston shell C is bored out in the chuck, finished up between centers and faced to length, and the groove for the piston ring cut in. The piston must be a good fit in the cylinder, without the least shake.

The first piston plug D is held in the chuck and finished all over at one setting, so that it will tap in the piston shell C. The slot for the connecting rod is milled out.

The piston ring is made of steel, bored and turned in the chuck, cut off and fitted to the groove in the piston shell, then cut at an angle of 45° with a fine hack saw. Finish out with a file and spring into the groove in the piston shell. But putting the ring in position will be left till the assembling operations. The shell C and plug D are placed in position, and the 3-16 in. hole for the wrist pin Fdrilled and reamed. The wrist pin and the slot for the connecting rod must be exactly square so that the head of the connecting rod E will not bind and cause friction.

The 1/8 set screw holds all three, C, D and F in position. .Fis the wrist pin, made of 3 16 in. Stubs steel, and requires no turning. The connecting rod E is one universally used, and the machining operation is so simple that it will not be described. The two crank discs and shaft are made in one piece from steel.

They are turned between centers and finished both the same size. The hole for the crank pin G must be exactly the same in both pieces from the center; these should be drilled and reamed together to insure that these holes match. The crank pin G is turned between centers; the ends that fit the discs must drive and be left about 1-32 in. long, to allow for rivetting. The right hand shaft is turned smaller for the crank eccentric L to fit on the end.

The bottom of the two main bearings II are faced off between centers, mounted on a small angle plate and bored out, reamed to 3/8 in. and faced to width on a| in. mandrel. Drill two holes in the bottom of each of the main bearings to hold them in position on the bed M. The bed M is strapped to the face plates and the top faced off. The fly wheel N is bored out and reamed to 3/8 in. diameter and finished on a 3/8 in. mandrel between centers.

The crank eccentric L is to be made from steel. It is chucked and bored out to fit snugly on the 1/4 in. diameter end of the crank shaft, with a small square pointed tool. A piece of 5-16 in. steel rod is held in the chuck and turned to lit the 1/4 in. hole as a mandrel, and turned on all the surfaces and polished at one setting. Lay out the stroke of the eccentric 1/8 in. from the center and drill with a 6-64 in. tap drill and tap out with a 9 64-32 thread. The eccentric is held in position on the shaft with a 1-16 in. jib screw.

The valve rod K is made from 3-16 x1/4 in. cold rolled steel, turned between centers, threaded on the top end for a 7-64 in. nut to hold the valve Q in position. The bottom end is slotted to receive the eccentric rod J. A 1/8 in. hole is drilled for a 1/8 in. bolt to hold the two together.

The valve rod I is drilled and reamed to 1/8 in. diameter, and threaded with 1/4-32 thread, to screw in the valve rod stuffing box P. P is the valve rod stuffing box. All the machinery operation is done at one setting in the chuck, and it is to be sweated into the 3/8 in. bore of the valve chest.

The valve Q is drilled, reamed and finished in the chuck. It should be ground with ground glass and oil to make a steam-tight sliding fit. P is the exhaust bushing. This must be turned on a mandrel, tapped the size for a 5-16-32 thread, turned and a 7-16-32 thread cut on one end 3 16 in. long, to fit the top of the valve chest.

The mandrel can now be forced out and the bushing be screwed in position in the valve chest, and the hole formerly occupied by the mandrel tapped out 5-16-32, V thread for the exhaust pipe. The eccentric red J is filed out of 1-16 in. sheet steel, drilled and reamed on the eccentric end to 5-32 in. and the valve-rod end 1/8 in.

Two brass washers are required 5-16 in. diameter and 1-32 in. thick, one between the eccentric rod and crank eccentric, and one on the outside. The peep hole cover is made by pouring babbitt surrounded by fire clay and fastened to the outside with two 1-16 in. screw's not shown in the drawing.

In assembling the various parts, see that there are no burrs in the cylinder or valve chest, or any working part. As all the parts have a letter given on the drawings, the builder will have no trouble in locating the-parts as they are to be assembled.

An advantage as a steam raising fuel possessed by oil as compared with coal is the remarkably steady steam pressure which may be obtained by means of the liquid fuel. This is due to the fact that the oil fires do not require the periodical, and automatic logs of steam pressures on ships using oil as fuel can easily be made to show as little as two pounds maximum variation of pressure for a run of 27 hours or more. This of course, conduce to economy in the operation of the boiler, which is under conditions that are kept constant, instead of having the 30 per cent drop in pressure which is sometimes noted on an overloaded boiler when it is found necessary to clean the fires.