Software for cutting prime spur gears on gear hobbing machines with a differential

It's for cutting prime spur gears on gear hobbing machines that have their differential located before the index gears. Mostly Gould and Eberhardts, but there are others built this way too.

I started working on this a few months ago--I had to stop because of a big backlog of work at the shop.

This is the first permanent running release (The initial iterations timed-out to keep me from spreading untested software too far).

Try it and see if it works for you. Click here

Of course you will probably need to add/remove intermediate gears to get things synced.

If I had a nickel for every hour I plodded through logs of gear pairs.... Now a program.

Will it do lead ratios? I got a little app from Carlstedt that does two and four gear tooth counts from train ratios. that works for prime indexes - provided you can tolerate a tiny bit of lead.

Gotta play with G_E Diff. More later.

Forrest Addy said:

Will it do lead ratios?

Click to expand...

Hello Forrest,

Yes, it does index, lead and feed... caveat: Differential must be located before the index gears for this to work... (Hobbers with diff after Index is for later).

--david

Oops. I just got a new compiler and I forgot to set it to generate code that includes operating on Windows XP. That is fixed now.

This is my first effort for the barber colman hobbing machines (it's very rough at this point): Click here and choose the one labeled: B-C_Diff_Spur.exe.

Right now I need to know if you all agree that the math is right. I included 'C' and 'L' constants used in the returned values to make it easier to check. I have been using 12 as the index constant, 5 as the diff constant and .075 for the feed C.

if it fails to return the index or lead gear sets, add more change gears or add another start or two to the hobb.

If you have the time, I would very much appreciate it if you would check it out and give me some feed back.

I'll work on the next step if the math is right. That will be to give lots of gear sets to choose from and dig deeper for feeds with a smaller error.

Thanks! --david

It seems to be working well. The ones I checked were right. Use the link above if you would like to try it...

Next, I plan to do one for cutting helical gears without using the differential.

As I begin to write a program for solving: 'Helical gears cut non-differentially', I would like to ask some questions.

Do you use one of these formulas for finding the index gearing, or another one?

K = Machine index constant
C = C constant
N = Number of teeth

KCT/(CN) +or- 1

or Lead method

L = Lead
F = Feed

C' = L/F

C'/C' +or- 1 x KT/N

Do you believe that the C constant can consist of a number that has a fractional part?

If so, does it need to be a rational number?

This is a program for cutting helical gears non-differentially. It's likely to have bugs in this first version, be warned.


Click here and download--or run/try in place without downloading--'Helical_B-C.exe' It is intended for many Barber-Colman Hobbing Machines, such as: 6-10, 6-16, 6-20, 16-16, 16-36 and 16-56.


--david