Posted by gearhead1 on April 05, 2013 at 12:39:12:
In Reply to: Re: Hobbing Prime Spurs using differential posted by BillS on April 04, 2013 at 10:32:24:
I finally figured it out.
And it works.
Good Gods, I'm tired. But it works and now I know how.
I'll skip the long story and cut right to the chase -
On _this_ Koepfer 173, one has to modify the feed for helical gears ( or any time using the differential )by dividing the feed desired by the Cosine of the Helix Angle.
So, for -
Fh = Feedrate to use with Helical Gear Differential
Fd = Feedrate desired
cosHA = Cosine of the Helix Angle
Fh = Fd / cosHA
And I successfully hobbed a 71T Spur gear without having a 71T Spur gear.
Now to make a 79T... Thanks for the information and assistance, Bill. I appreciate it.