Stealth Pilot wrote:

Trevor thanks for the gear info. I could not find it anywhere.
I dont know whether you are being pessimistic about the ML7 or not.
I guess I'll find out.
In all I want to remake 12 gears in cast iron. how hard could it be?

the model diesel engines will come later.

TUMESFFF



Can you track down a copy of George H Thomas's books? He designed, and
had published in Model Engieer, among other things, a variant of the
Radford dividing attachment, that is, while mainly for the S7, shown
modified in a chapter on the ML7 and discusses at lenth, the
capabilities that are available using the 65 tooth gear.

In there, I am certain that the DP and PA of the bull gears is
mentioned, as he discusses and shows his math for, the making of a worm
that will engage the bull gear.

Of course, you could work it out from the diameter and tooth count.

Leave the Ivan Law book in the loo, and absorb it in small doses. Each
time you go through it, a few more bits of the puzzle will fall into place.

It is reasonably safe to say that the gears would be 14.5 degrees PA,
as they were pretty much the norm. Same as an Acme screw thread cutting
tool, which I doubt is a coincidence.

Making gears on manual machines is actually quite easy. Not drooling
on yourself, and not losing your place on the dividing head, are the
major challenges. Usually the state of mind that brings on the former,
is responsible for the latter.
Direct indexing off of borrowed gears is the way! :-)

Just keep in mind that you do not mill teeth, but the spaces between them!

Do you have a foundry in your area that will entertain small lot
castings? Planning on using iron barstock?

Cheers
Trevor Jones