Posted by Tom Ramsey on May 26, 2009 at 10:06:33:
In Reply to: Test radius posted by T.Fujikawa on May 25, 2009 at 16:52:30:
Take the test radius of the master gear plus the maximum test radius of the gear tolerance divided by 2. Then add the actual bore size of the master gear plus the bore size of the gear in question and divide that by 2. Add the two results and that is your jo-block gage length. You must have the same pressure angle. The helical gear test radius is a function of the pitch diameter and the helix angle but you can use a straight tooth master if you have a tester with an adjustable helix. Hope this helps.