Posted by Bill S on April 07, 2005 at 09:29:31:
In Reply to: Problem with customer design posted by Charley on April 06, 2005 at 09:33:20:
The reduction in worm OD will affect the lead angle of the worm and thus the table setting for throating the gear (are you throating the gear?).
If your are not throating the gear but are cutting it as helical, just be sure of the helix angle the gear should have and you will be fine.
You won't have to worry about tolerance allowances in mounting misalignments other than center to center distance tolerance.
If throating, you shouldn't see a problem in cutting the gear, just that the throat radius of curvature in the gear OD will be slightly larger. Throat radius is supposed to be slightly larger than worm radius (comparing at pitch lines and root lines) to allow for tolerances in mounting alignments and to encourage proper lubrication.
You will probably want to fixture a worm and worm gear in correct mesh and check the contact pattern with blueing and check for backlash. If the contact pattern is in the middle of the face you should be Ok.
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