290 



Popular Science MonMy 



tubing y2 •"• 



1^2 in. outside diameter. This 

 piece will be long enough to give the 

 ports and intake as well as the steam- 

 chest. Cut a piece 8 ins. long for the 

 steam-chest. Square up both ends with 

 a file and remove all burrs from the 

 inside end with the point of a knife- 

 blade. Next measure in from each end 

 of the pipe ] 2 in. and drill a }/i-m. hole 

 at each of these points for the ports. 

 Be sure to drill the holes on the same 

 side of the pipe. 



The ports P shown in Plate 2 are 

 made from the piece of tubing left from 

 the steam-chest by cutting two pieces 

 each ^4 in. long. File one end of 

 each to fit the steam-chest tube and the 

 other end to fit the cylinder tubing. 

 Solder these pieces to the steam-chest 

 over the holes drilled for the ports. A 

 }-i-in. hole is next drilled }i in. from the 

 cylinder heads in each of the cylinders, 

 after which they are temporarily fast- 

 ened in position on the cylinder support 

 with these holes on top. Next solder 

 the other end of the port pipes to the 

 cylinders. Remove all burrs from the 

 inside of the steam-chest and cylinders 

 with file, emery-paper or knife-blade. 



The slide valve-rod is made from a 

 piece of H in. brass rod 9 ins. long. It 

 is first bent to 

 the shape and 

 flattened on the 

 end as shown, 

 SVR in Plate 2. 

 Next file two 

 notches around 

 the rod. These 

 are about >4 in. 

 wide and not 

 quite 1/16 in. 

 deep. The cen- 

 ter of the first 

 one is located 

 1)4 ins. from 

 the center of the 

 3/16-in. hole, 

 which is drilled 



in the flattened end for the bolt. 

 The center of the other one is made 

 exactly 7 ins. from the first one. Be 

 careful to get these properly located 

 as it is the most important pari <A tiie 

 engine. 



The slide valves are cast on the slide 

 valve-rod just described. Use babbitt 



Plate 2. Construction details of the slide valves 



metal for this. A piece of the 3^-in. 

 tubing ^8 in. long is first worked out 

 and all burrs removed from the inside. 

 A H-in. hole is bored in a board 

 ^8 inch. deep. In the center of this 

 hole the M-in. bit is placed and the 

 hole bored on through the board. Now 

 place the small piece of pipe in the J^^-in. 

 hole and slip the vaK^e-rod into the },<i-m. 

 hole, passing it down until the first 

 notch is in the center of the pipe. The 

 valve may be cast by running the pipe 

 full of babbitt. Carefully remove from 

 the mold and set it up for the other 

 valve, using the same piece of pipe. 

 When both valves are cast in place they 

 are carefully fitted into position in the 

 steam-chest. If they are found to fit 

 too tight they may be scraped very 

 lightly with a knife. 



From the piece of i32-'n. pipe left 

 from the cylinders make the eccentric 

 ring. This is made just }/2 in. wide. 

 After it has been carefully worked into 

 form and the edges rounded a trifle on 

 the inside as well as out it must be used 

 to cast the eccentric and piston-heads. 



The small piece of pipe is then fitted 

 and soldered to it, as shown in Plate 3. 



The purpose of the eccentric is to 

 throw the valves first to one side of the 

 ports and then to the other. 

 The eccentric mold shown in 

 Plate 3 is used to produce the 

 casting for the eccentric. In 

 making the mold the expansive 

 bit is used to bore a hole }y in. 

 deep in a block 

 of wood. This 

 hole should per- 

 mit the eccen- 

 tric ring to come 

 into it evenly. 

 After this hole 

 has been 

 smoothed the 

 3^8-in. hole men- 

 tioned above is 

 Ijored as well as 

 of the center for 



one on the other side 

 pouring the metal. 



Prepare the mold for pouring by 

 installing the brass ring. After turning 

 the o]>en face of the mold down on a 

 piece of paper laid on the bench and 

 sciuaring up the piece of ^ in. steel, 

 the mold may be poured. 



