Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

When I had the piston out to cut 100/1000 off the top, I also added a tiny chamfer (so small it nearly unnoticeable)to the top and bottom of the piston. I also used some #1200 paper and Maas or Simichrome and gave the entire piston a good rub by hand against a folded towel on the table top. This actually took a little of the coating off the bottom of the skirt. The bore had a few very minor scrapes so I bent a coat hanger wire to hold a folded strip of #1200 paper about 6 " long dripping with WD-40 and gave the bore a quick "honing" followed by a cloth strip with Maas or Simichrome that was large enough to fit the bore fairly tightly. I spun this with an electric drill. (the sandpaper strip spun by a Dremel tool on the slowest setting). This took care of the very minor scoring that was on the cylinder wall. Perhaps I went a bit overboard but it sure did work well. Only one O-ring went back on the piston.

The result was a very smooth running engine that fired 24 times per minute and ran for a very long time (nearly 5 hours) on a single fill-up. I also add a couple drops of oil to the skirt and lower bore before firing and once or twice during the run.

Gil