Posted by BillS on September 22, 2015 at 07:42:58:
In Reply to: 16 - 36 Differential Formula posted by Mark S. on September 17, 2015 at 14:18:37:
Hi Mark,
There is a Barber Coleman 16-36 listed in the FAQ which is a type "B".
The Differential Formula is:
0.2387324 x sin(Helix Angle) x NDP
Ratio = ----------------------------------------------
Teeth to cut x hob starts
I show that machine to have an index = 15/Teeth and feed of 0.0375 inch per rev of workpiece.
It is called Type B (based on CPC-HOB) because the differential gear ratio changes inversely with number of teeth to cut.
I don't list machines by serial number, so I don't know if your machine is type A or B. If the formula doesn't work for you, please let me know.
There are several methods to find the formula and the machine type in the FAQ. Also if you have a manual for your machine you could send me a copy
and I could send you the formula.