In article ,
"Dave August" wrote:

Jeez,

I use the same (well mine's a knock off but..) tool post and blades...

Crossslide only, Understood that it "should" work on the compound, since
mine "does" work... Just trying to come up with a simple test to eliminate
things...

Clausing might be right, time to try the spindle nut test.

I just tightened the spindle bearing adjustment nut. It made a huge
difference. Now that I think about it, the headstock never got warm
after running a while, and it's supposed to get warm but not too hot to
touch.

Joe Gwinn



Keep us.. "posted".. :-)

--.- ave

"Joseph Gwinn" wrote in message
...
In article ,
"Dave August" wrote:

I haven't had any issues with cutoff work.

What's your tool post?

Aloris BXA bolted (5/8-20) to the the T-slot in the standard-issue
compound.


What kind of cutoff tool?

BXA-7 and also SGIH 19-2 blade held in a Dorian BXA 7-71C.

I get chatter even when the SGIH blade et al are mounted upsidedown and
the lather run in reverse, which eliminates self-feeding as a cause.

Oddly, the upsidedown SGIH works fine when the work is held in a collet,
but chatters if the work is in a 3-jaw chuck. The chuck does not appear
to be worn, but its length implies that the cutting point is an added 5"
or 6" farther from the spindle bearings.


Have you tried a test with the cutoff tool mounted directly to the cross
slide and not on the compound, that's what I had to do on the "import"...

This I have not tried, and would require some fabrication. An
alternative would be to over-tighten the gibs of the compound. But, the
lathe ought to be able to make such cutoffs without bypassing the
compound, which is why I have kept on trying.

Gunnar suggested locking the lower gibs and using only the compound to
advance the blade. I did this some time ago and it had no effect, but
it may be time to repeat the exercise.


My suspicion is focused on the cross-slide slideway and gibs, as when I
put a 5-foot long 1" bar in the boring bar holder perpendicular to the
bed ways and tug up and down on the bar, which is centered in the holder
so the bar's own weight balances out. I feel motion only in the
cross-slide gap when I tug on the bar.

The problem is that this is a very severe test, and I don't know how
much motion is to be expected for a lathe of this size and heft, even if
it were new.


Clausing has also suggested that I tighten the spindle adjustment nut by
1/4 turn. This is today's project. I may have to fabricate a
radial-pin spanner wrench to do this.


Joe Gwinn