Daniel A. Mitchell wrote:
Joe AutoDrill wrote:

Yes, a 1.5" hole in SS would be a heavy job even for a BP. You might
consider one of the 'Rotabroach' type annular cutters. These require a lot
less power to 'drill' a hole.


Ditto that. The Rotabroach tooling works like a charm as long as you use
plenty of coolant. Otherwise, you can easily get lulled into a false sense
of security with them and burn 'em out.
Yup! And back them out an clear them frequently when drilling deep
holes, as the small flutes tend to clog easily.

On the plus side, they leave a very round hole with a good interior
finish. Almost as good as reaming. Hole size regulation isn't too good,
but likely as good as with a drill. You can always ream or bore after if
a better hole is needed.

If all you need is a decent large hole, and all you have is a small
machine, they're an excellent option.

Plus, you end up with all those nice little round plugs left over to
make something else out of! :-)

I did win a Rotabroach on Ebay yesterday.(I'd just have to find out if
any 1-7/16" cutters are available for it.

All this talk about stainless steel is making me think again about
using Delrin instead. It would be much easier to drill or mill out
those little bearing cups in Delrin, and I would think that the
bearings would roll in Delrin with less friction than in stainless
steel. The Delrin may not last as long, but the bearings themselves
would actually last longer, and I don't think I'd need to grease them.

Thanks.

Darren Harris
Staten Island, New York.