Wots the bore centres George? haven't got the scans on this computer.
Regards Ian.
Hi Ian,
The centers shown on the booklet that is available on the build is 1.125".
What I never could understand when I built mine from stock material is the 1.062" from top face of cylinder to bottom face to accommodate either 1/2" stroke or 5/8" stroke so it was a mater of working out from piston thickness + the 1/32" register top and bottom + the steam gap of 1/32" top and bottom to establish what the cylinder thickness would be..
So the swept volume of the cylinder in a 5/8" stroke engine with a 1/4" thk piston would be 5/8" stroke + 1/4" thk piston + 1/8" for the register and clearance top and bottom would be 1" but that does not include clearance for the nut on the piston head.
From memory I fixed the piston to the rod as per Stuart D10 without the nut, if it wasn't so cold and wet I would have gone down to the work shop to check the drawing that I worked from making the engine 5/8" bore x 5/8" stroke and it was piston valve.
Hope this helps
George.