On Mon, 06 Jan 2014 00:52:04 GMT, Doug White
wrote:

"Wild_Bill" wrote in
:

Ball end mill cutters are generally side cutting, in that there is
very little/none cutting at the tip of the ball, unless you can source
cutters that are similar to split-point drills.
The same goes for countersink cutters.. they're just not as effective
without a properly sized hole to feed into.

Because the geometry, which has a shallow hole in the center, the ball
end mills actually cut just fine, and in fact, most ball end mills are
center cutting anyway. The pins are just a little larger than 7/32", so
I actually got one that size, and a 13/64" one as well. My theory was
that the smaller one would cut preferentially, so the big one would be
"fixed".

Well, it worked! I put the 7/32" ball-end cutter in the headstock of my
lathe, and the ball-end 13/64" cutter in the tailstock, disengaged the
gears, and rotated the spindle by hand. Contrary to plan, the smaller
cutter stayed put, and the larger one did all the cutting, but such is
life... The next time (if there is one) I will reverse the position of
the cutters for a better view of things. The cutter chatters a bit, but
by the time I got to the critical point, it had pretty well centered
itself.

Because there was less margin for error in centering, I carefully placed
the best centered swage end of each pin towards the larger cutter. I
could easily control the depth with the tailstock handwheel, and snuck
up on the cut. It actually took a lot more cutting than I expected to
get the pins to the point where they would drive out with a good blow
with a fairly heavy hammer. Tapping with a small hammer got me nowhere.
From the point where it first started cutting, I had to advance 35 to 40
mils to get the pins to drive out.

Once they were out, I was amazed at how much the ends had been flared
out by the original swaging. The nominal OD of the pins is just under
5mm. I measured across the ends that were unmolested, and one pin was
mashed out to 5.6mm, and the second one was 5.4mm.

I've got a selection of different OD ball bearings to choose from to
flare the new pins, but I'll need to make some plates with shallow holes
to hang onto & align them. It will be interesting to see if my 3 ton
arbor press will produce enough flare, or it I will need one of my
wife's sledge hammers.

Thanks for all the suggestions! Once I had a good plan of attack, this
all worked very nicely.

Doug White
=====================

Thanks for the feedback. Very informative thread.


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"