Pile of parts from eBay

[The_Paso_Kid]

I just received some steam engine parts that I bought on eBay. It is incomplete, and missing plans. The cylinder that came with it is significantly larger than the piston itself and probably went to another engine. The frame is soft soldered together and had come loose during shipping so I will have to secure it. There is a bit of a bind in the crosshead at the top of the stroke. Otherwise it should be a fairly simple build. I think that I will use a simple piston type valve rather than making a steam chest with slide valve.

 

[The_Paso_Kid]

First step was making a new cylinder to fit the piston. I rotated the shaft to put the piston at top dead center and took measurements to figure out the necessary length. Then measured the piston to determine the proper bore size. I first drilled then used a boring bar to achieve the proper fit for the piston. I will now have to mark the cylinder for the bolts to hold it in place.

 

[The_Paso_Kid]

The boring bar made a fairly smooth internal cut and the piston slides in the cylinder, so I don't think that I will have to do any lapping. Next piece to make will be the end cap for the cylinder.

 

[The_Paso_Kid]

While rotating the axle to move the piston I notice a slight bind. I also noticed that the frame would flex during the rotation of the axle. I removed the axle and cam assemble from the frame and chucked it up into the small lathe. Instead of using the dial indicator I just used one of the cutters in the tool post and "eyeballed" the axle for trueness while rotating the chuck by hand. The axle was definitely misaligned and the cam discs were slightly out of parallel. A few small taps with the small hammer was all that was needed. I then replaced the assemble into the frame and tested it again. No more binding and no movement in the frame as well.

 

[The_Paso_Kid]

I machined the end cap for the cylinder out of aluminum and used the milling machine to drill and tap the bolt holes to hold it in place. I started by drilling body size through the end cap then the tap size in the cylinder itself, followed by a 4-40 tap. I then secured the end cap in place with a cap head screw so that the end cap did not shift or move while drilling and tapping the other 5 holes.

 

[The_Paso_Kid]

I used one cap head screw to hold the cylinder in place so that I could figure out where the valve would go. The eccentric was already built so all I had to do was make a rod to connect it to the valve. The threads for the eccentric rod had already been tapped and were 3-48 so all I had to do was turn down a portion of a steel rod down to the size of a #3 and then thread it with a die. I attached the rod to the eccentric and used the rod to determine where the valve should be located in relationship to the cylinder.

 

[The_Paso_Kid]

I used a square to draw a witness mark on the end of the cylinder on the valve side so that I could properly align the cylinder in the vice on the milling machine for the next machining operations.

 

[The_Paso_Kid]

I set the cylinder to the side of the piston and rotated the axle so that I could mark where the steam inlet holes were to be drilled.

 

[The_Paso_Kid]

I leveled the cylinder in the vice using the witness mark and then drilled the two steam inlets to the cylinder.

 

[The_Paso_Kid]

I next took a 3/8" endmill and milled a slot into the side of the cylinder where the block containing the valve will be attached. I could have just milled a flat edge onto the cylinder and soldered the valve block in place, however since I had the thickness of material on the cylinder to do so I milled in a slot which would better hold and align the valve while soldering it into place.

 

[The_Paso_Kid]

I again temporarily bolted the cylinder back onto the frame. I then took a block of 3/8" thick brass plate and cut off a piece to be made into the valve cylinder. I placed this block into the slot in the cylinder and used the rod attached to the eccentric to mark where to drill the hole for the valve cylinder and then marked where the steam inlet holes go into the main cylinder.

 

[The_Paso_Kid]

I rotated the axle and marked the eccentric rod where it was at both top and bottom of its stroke. The stroke was close to 1/4." I then did a few calculations on paper and determined approximately where the intake and exhaust sections on the valve would be. I then used those measurements to finish working on the valve block.

 

[The_Paso_Kid]

I milled some steam passageways into the end of the valve block that will be soldered onto the cylinder to make the connections between the inlets on the cylinder and the inlets on the valve block. I did it this way so that the valve block would not be longer than the main driving cylinder.

 

[The_Paso_Kid]

It took awhile to heat the massive cylinder and valve block to get the solder to flow into the joints. I had a C-clamp holding the two parts tightly together and I used paste flux and a small amount of acid core solder. After cooling the parts I used the air compressor to check that the steam inlets had not been clogged with solder. I then used a bit of steel wool to clean up the tarnish from the heating and soldering of the parts.

 

[The_Paso_Kid]

I then attached the cylinder to the frame using some 4-40 hex head bolts and then attached the end cap to the cylinder with the same type bolts. The socket head cap screws I was using to temporarily attach the cylinder to the frame would have worked, but I liked the look of the hex head bolts.

 

[The_Paso_Kid]

I cut the rod attached to the eccentric to its final length and filed the end down to form a tenon so that I can attach it to the valve.

 

[The_Paso_Kid]

I hand filed the notch in the valve to accept the rod.

 

[The_Paso_Kid]

I inserted the file I used to cut the notch in the valve and used it level it in the vice so that I could drill the pin hole perpendicular to the slot.

 

[The_Paso_Kid]

After inserting the valve blank into the valve cylinder I attached the rod to it and rotated the axle so that the eccentric was at top-dead-center. I then used a drill in the flex-cable drill to lightly mark the positions for both the upper and lower inlets on the valve blank. I then rotated the axle another 180-degrees so that the eccentric was at the bottom of its stroke. I then marked the valve blank with the drill in both inlet holes.

 

[The_Paso_Kid]

I removed the valve blank and using the dimples from the drill I marked the sections of the valve blank that needed to be turned down to form the steam passageways for both intake and exhaust. I turned it in the lathe and reinserted the valve to test it. I was so excited that I was nearly done that I neglected to snap a photo of the completed valve body.