Re: [CAD_CAM_EDM_DRO] Re: Cool Worm Gear

>
> --- In CAD_CAM_EDM_DRO@egroups.com, paul@a... wrote:
> > I made a worm gear for an acme thread when I made a threading dial
> for
> > my lathe. I found it useful to gash the gear blank before hobbing
> > it; it made it cut the right number of teeth w/o a problem.
> >
> > Paul
> >
> Wally Replied:
>
> What does gash mean.
>

You index it around and make cuts (angled appropriately) so you, in
effect, rough out where the teeth will be. When you run the blank
against the hob, the hob will run in the cuts and cut the correct
number of teeth.

If you don't do that, you run the risk of cutting the wrong number of
teeth as the hob runs on the circumference of the blank. It's possible
to do it this way, but gashing it pretty much gaurantees cutting
the correct number of teeth.

I did it by mounting the blank on an arbor in a spin indexer, which
was mounted in my mill vice. The indexer was tilted to get the correct
angle on the blank and then cut with a slitting saw. Fortunately, the
number of teeth I needed could be done with an indexer, otherwise you
might have to use a dividing head.

Making the acme hob was more fun. It wasn't until I finished the
first one that I realized that I needed a left handed thread, not
a right handed one.

Paul

--
Paul Amaranth | Rochester MI, USA
Aurora Group, Inc. | Systems & Software
paul@... | Unix / Windows / NT