Hi John
Contraption??!!
Its a half built IC engine, based roughly on one of Brian Rupnow's designs, he gives them all names but I have forgotten which one I used for inspiration but it has an overhead cam.
Having built a Potty mill engine and a Monitor I thought I should make an IC engine but stalled when it came to making the cams. I do not have a dividing head and could not see an easy way. The model got pushed to the back and I made a Corliss instead, in the photo you can see a scrap cylinder, milled the steam chest too deep.
I do plan to finish the IC engine, just waiting for the right inspiration to come along.
Andrew