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

Arnold

Thank you very much for the information.  As I mentioned I got the 7.8mm diameter, but my .8mm thread gauge was too fine, it did not slip in.  I tried a second gauge and got the same result.  They were close but the 32 tpi fit exactly.  Either is going to work.  I figured it would be easy to make the metric thread on my little Cowells  or Myford lathe.  i will need to borrow a concave knurl.  The rest should work out.  I think the reason 7.8 x .8 mm is .309" x .0314" pitch and the ME thread 5/16 x 32 tpi i.e. .312" x .0313" pitch, virtually identical.

When I get this done I will publish the result.

Happy New Year

Bob