Posted by Tom Ramsey on March 22, 2010 at 13:02:07:
In Reply to: non differential hobbing feed change gears posted by inshaa on March 10, 2010 at 12:32:16:
The formula is
Feed Required divided by .0375 eguals A/B x C/D.
You can use a Barber Colman feed chart for the 12N machine (.075 feed) and divide the A or C by 2.
.012/.0375=.32
30/60 x 48/75=.32
.03/.0375=.8
40 x idler x 60=.8