From: muratlanne@gmail.com   
      
   "Clare Snyder"  wrote in message   
   news:obp86k1p035jdb1f67oo4ht0ufbkm5goab@4ax.com...   
      
   I had the students practice their "fitting" (mostly filing) by making   
   piston rings for the 2 strokes out of cast iron pipe  - 5 of the 15   
   students actually got their engines to fire up!!!!   
   --------------------------------------------------------------   
   How did you teach them to file square?   
      
   I've used the tops of vise jaw inserts as a guide but that's hard on the   
   files and the vise. I made an adjustable roller guide to file the teeth of   
   my sawmill bands evenly at the factory angle.   
      
   Before Eli Whitney invented a milling machine for the task he made filing   
   guides for musket lock parts so they would be reasonably interchangeable.   
   https://commons.wikimedia.org/wiki/File:Eli_Whitney_milling_mach   
   ne_1818--001.png   
   It or a similar one is in the American Precision Museum in Vermont.   
      
   The parts aren't easy to make:   
   https://www.dixiegunworks.com/index/page/product/product_id/2171   
   category/524/category_chain/392,520,521,524/product_name/GP6102+   
   umbler+%28repro.%29+for+Dixie+Charleville+1777+Musket+and+1816+Musket   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)