I have been playing about all week modelling Stew Harts Popcorn engine. Stew kindly sent me a package of 2D drawings that he had created, and it looked so interesting that I promptly set about modelling it in 3D. I discovered a couple of missing dimensions, and informed Stew, and as I modelled it I kept Stews metric dimensions for everything except the fasteners and the shaft sizes. ----and the piston diameter----And the bore of the crosshead guide. Those I converted to the closest British Imperial sizes. I have no desire to start a thread that competes with the fine work Stew is doing, but I thought that probably interested model machinists might want to see what the engine looked like as a 3D model. There was no base drawing in the package received, so I "Made one up" that would do the job. If any of you CAD guys out there want a copy I have saved these files as.xt and .iges. and as .step files and can post a link to a download.---Brian