Posted by BillS on May 20, 2009 at 21:08:19:
In Reply to: barber-colman 14-30 posted by dennis on May 19, 2009 at 09:10:13:
Change gear sets are equal to the ratios as you show them.
Let's say you want to cut a 50T gear with 15 deg helix.
Index = 12/n = 12/50
Index gear set must be exact match to 12/50
diff ratio = ----------------------
2 x ncp x Hob starts
Diff gear set should be as close an approximation to the calculated diff ratio above, but doesn't need to be exact.
There is more to setting up a hobber, plus some special situations, that are covered in the FAQ page of this site.
CPC-HOB, a PC program sold by Ash Gear & Supply, covers 99% of all the machines and situations likely to occur. You might want to consider it if you are planning to use this machine in a job shop environment.
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