"John R. Carroll" wrote in message
...
Jim Wilkins wrote:
On Feb 5, 10:43 pm, (John Normile) wrote:
...
My friend was told that the pinion was not available, and he would
need to buy the whole new rotator unit for something north of 5
grand. ...
John Normile
camperkn_at_yahoo_dot_com

Making an unavailable gear::
http://picasaweb.google.com/KB1DAL/H...10370886636434

The cutter was shaped to fit an undamaged tooth space in the broken
original.

That one is aluminum. How about Stressproof or 4140 Prehardened?

Better to break the pinion than the ring for one thing.
Make two and have an available spare.

--
John R. Carroll

But neither Stressproof nor a machineable hardness of 4140 is going to make
much of a pinion. Those things typically are loaded like crazy. If they're
through-hardened (the weakest heat treatment for a highly loaded gear, but
the most common), they're generally too hard to machine with ordinary tools
and machines.

Is this a straight-tooth pinion, or a spiral or hypoid? If it's one of the
latter, there aren't many shops that could make it, without a Gleason or
Liebherr gear generator, which means a custom gear maker. Not cheap. Even if
it's straight, it's not a heck of a lot easier. The teeth and the gullets
are tapered from one end to the other.

I'm wondering if the size of the set is close enough to that of a truck ring
and pinion that you could make that fit, or machine either one a bit to fit.

--
Ed Huntress