On 22 Feb 2012 03:38:52 GMT, "DoN. Nichols"
wrote:

On 2012-02-21, wrote:
SNIP
Yes -- and you need a long travel arbor press (or something
else) to drive the broach. And care to make sure that the driving force
is on axis so you don't bend and snap the broach. (Better are the draw
type, but they require a different style of driver -- ideally hydraulic,
I believe.)

Enjoy,
DoN.
Gretings DoN,
Regarding broaching using an arbor press, I have broached uncounted
keyways using arbor presses. Even with a good one it's possible for
the broach to start cutting at an angle. The method that has worked
best for me over the years is to start the broach, relieve the
pressure on the broach to let it spring back if it wants to, start
pushing on it again, relieve the pressure again, and the broach all
the way through.

Yes -- I've done the relax and let spring back as well. A good
approach.

Unless it's a long broach. Then I might repeat the
process a few more times. Most of the time the broach will not spring
back into the guide bushing a noticeable amount, but sometimes it will
and thats when you know you just avoided a scrapped part or a broken
broach.

And -- you may have to do it up to three times with some keyway
broaches with two shims needed. Real fun when you add a 3"+ hub to
broach, even in nice 12L14 free-machining steel. :-) At least the
outside keyway on that hub (actually a hub adaptor) could be done on the
horizontal mill itself before I pulled off the old pulleys.

Enjoy,
DoN.
I used to broach 3/8 keyways in steel and cast iron. On the big arbor
press I had to hang on the handle to force the broach through. Three
passes. I could have used the 40 ton air over hydraulic press but it
was too fast and might have broken a broach. Besides, I was young and
didn't really mind hanging from the press handle like a monkey.
Eric