I hope you don't mind a little update on the vertical back acting engine. I saw a thread on making globe valves with the PMResearch kit and that reminded me that George Brittnel had posted a thread sometime in the past about buillding globe valves from bar stock so I looked it up. Great stuff!
I didn't have the right stuff on hand so I got some ordered. I couldn't wait for the delivery so I started without it. Only enough stuff for one try and I didn't follow George's design exactly. George used a very small screw ( #0-80 or #1-72) and while my eyes are still good enough to see them on the bench, my fingers hate them and send them to the floor where they love to hide so the smallest thread on this valve is the stem thread, which is a #6-32, a very manageable size for me. I built a 90° style with side outlet which is much easier that the 180° with side control knob. When I get the ordered material, I'll try the 180° and maybe a gate valve as well. Here is a pic of the valve on the steam chest of the vertical engine. There is not room for a flanged mount so it is joined with a close nipple threaded #10-32.
I immediately discovered that this gave me far better control of the engine than I had using a cheap regulator in the air line. One of the features of steam engines is low speed torque which allows a load to be started and accelerated smoothly without the need for a clutch or low ratio gearing. It is difficult to demonstrate this on a small model and I was never able to demonstrate that in the past.
Here is a short video of the engine connected to a 5.5 to 1 step up gearbox, spinning my big brass baton. Since this is a single cylinder engine, the crank must be set a few degrees past TDC to get it to start, but it starts smoothly and accelerates slowly to about 100 RPM and can be controlled to run smoothly at about 25-30 RPM. Turn your sound up!
If anyone is interested in the globe valve, I can post a new thread after the supplies arrive next week.
Thanks for watching 7539
Jerry