Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

 I am leaving the piston aside for now, although good progress has been made with steel finishes.

Today I reviewed the cylinder, and elected to continue. I had not yet machined the cylinder to length, so that was today's job.

First thing I did was just to check parallelism of the faces and the bore, to reassure myself they had been made correctly - which they had. I was happy about that.

Then I mounted the cylinder in the 3 jaw, with my Edge Technology chuck spider to hold it square, and machined the opposite face.



The gland boss in this picture has to remain proud of the cylinder face by 1/8", so I'm turning from the inside out. I had originally thought about milling this face, but this seemed a better technique in the end. It worked out fine - I got the length within 0.001" of print according to my micrometer, so I'll take that.



I decided to start work on the various bosses and slots. The gland boss still had about .013" to come off to get to the right length, and although I could have done that while turning the face, I finished it in the mill.



For Christmas, I got one of these handy dandy gadgets. I must say, it makes centering a bore or a rod on the mill an absolute breeze.



I then proceeded to center drill and drill the features on the gland boss.



Unfortunately the gland boss ended up slightly off center relative to the holes and the face of the steam chest. When I machined the steam chest I did not quite judge the height of the face right. I don't think this will matter in the end, just doesn't look quite perfect. The drawings were a little unclear in that regard. Part of the learning experience. They should really give a dimension from the center of the bore to the face of the steam chest.

I also cleaned up the faces of the port bosses, but decided bot to drill the holes just yet.



What I want to do next is mill the 3 slots in the base of the steam chest, so I started getting that set up.



This is as far as I got today. I need to level the steam chest, then I can find the center of the chest from the cylinder faces. I think I will actually clamp the cylinder in a V block or something though, so that I can find the center of the bore as well. I should have machined the slots when I had the cylinder set up for the steam chest perhaps, but I should be able to get where I need to.

Anyway, good to be working on the engine again, hopefully more progress tomorrow.