DoN. Nichols wrote:
[...]

OK, I understand the procedure. Clearly this could have been done
neither as per the factory instruction nor using the kit provided.

Well ... it would have been possible to put the washer in there
behind the soft jaws and in contact with the master jaws.

I did not think I could get it in there - too big.

[...]

I did that and then turned and faced a 4.5" washer. The bottom
cleared the ways by about 1/8" and getting to the side of the disk
was a little tricky.

That is what the soft jaws are for. If the washer (or other
disc) is thinner than the steps of the jaws on the 4-jaw, you take a
new set of soft jaws for the 3-jaw, and turn them (after preloading)
to a step just deep enough to allow facing both sides. You can
actually make it a little deeper, and just expect to machine off a
bit of the height of the soft jaws as you do the first workpiece.
Remember -- the parts of the soft jaws are expendable. :-)

Yes. Just as well. I have already started expending them! With the 4-jaw I
just shimmed the workpiece.

Not to mention doing it at 575 rpm...

I would swear that mine will go slower than that. How many belt
steps are on your pulleys?

6. The biggest ratio is about 3, the motor runs at 1725. The figure is also
quoted by the Taig manufacturer.

And you could replace the motor with a three phase or a DC motor
and connect an appropriate controller to it to get speeds perhaps
1/6th your current speed. That would take you down to 100 RPM or a
bit slower. My 12" Clausing will go down to 210 RPM in direct drive,
and if I engage the back gear, it will go down to 35 RPM. The
corresponding highest speeds are 1600 RPM and 270 RPM. Having a
variable speed motor would be somewhat the equivalent of having a
back gear -- except that it would not boost the torque the way a back
gear does.

Or I could make a counter-shaft. Or spend $588 on a 7x8 and tweak the
controller - apparently one can get it from minimum 200 rpm down to 75. Or
(drum roll!!) I could use my RedNeck lathe which goes down to 80 (once I got
it on a stand and sorted out the tooling arrangement - no more than 3 years
from now...).

[...]
I started up on that. Inadvertently. The first parting tool I made
just did not cut it. It spun the toolpost and shaved the jaws before
I realized what was going on.

Clamp some heavy paper between the toolpost and the table or
compound and it will increase the holding power by fitting into

OK. Presumably there is a trade-off between the paper thickness and the need
to adjust the tool height. But with my little post that should not be an
issue.

But the advice on turning the OD jaws is noted. I also found some
good stuff he
http://www.ctemag.com/pdf/2002/0203-topchoices.pdf

related to what the shape of the jaws should be etc.

Of course, this is written from the perspective of someone who
is after 0.0001" runout -- and is working with a machine capable of
that. :-)

Isn't everybody?

[...]

OTOH the second (re-worked) parting tool works just fine. Once you
get past the squealing and screeching of the bigger OD down to about
3/8" :-)

Keeping the amount or projection down to a minimum helps a lot.
Making sure that the sides of the parting tool are parallel and
perpendicular to the axis of the workpiece helps. Having the parting
happening as close to the chuck's jaws as possible helps. Getting
lubricant to the bottom of the groove helps. And ideally, not having
a compound as part of the stackup will help minimize the flex of the
system.

Done all of the above. Still squeals like a banshee. But it is better than
it was with the original grind. Still have to keep backing out and clearing
out the chips before the tool digs in and stops the spindle - even when it
reaches the small diameter.

--
Michael Koblic
Campbell River, BC