I made a double acting oscillating steam engine from the plans by Eric-Jan Stroetinga. I have a close-to-stock engine detailed on my web site at: http://members.shaw.ca/rpape or http://members.shaw.ca/clc_switcher. I can provide the plans in the original metric, or my english measure conversion to any one who wants them. Eric-Jan has given me permission to post them. The engine took me about 15 days to build. I'm not a machinist by trade and don't really know what I'm doing. I'm good at math, though, so the valves are right. I made DXF 3d drawing of the most difficult to maunfacture part on the web page with a Java DXF viewer to view it.