Valve Gear Design for Steam Engines - My approach

[Charles Lamont]

In the era of steam locomotives with inside cylinders with valves between, they were very tight for space and the valve was usually driven by a rectangular buckle. There was not much clearance between the backs of the valves, so the valve rods from the buckles were cranked inside the steam chest towards the portface to allow room for the two glands and the drive knuckles.

 

[Richard Hed]

I can't see a sleeve on the Kirk drawing, just nuts which would make it hard to set the position as the single nuts could come loose. You either want a sleeve between the two nuts so they can be done up tight against it or you want nuts and locknuts either side. Either way you need to be able to swing a spanner and the nuts should not clamp down against the valve as it still needs to move off the port face to prevent a hydraulic lock if condensate builds up in the cylinder

My Fowler Traction engine has the lock nutted option and is true to what the full size also had. I think the rest of the steam engines with slide valves all have the slot and rectangular nut.

I'm glad to see this style. In all the years i've been studying this, I've never seen that. What a surprize.