In article ,
Nick Mueller wrote:

Joseph Gwinn wrote:

Learning how to part off initially takes some nerves and maybe some
blades you will break 'till you got it.

I haven't broken any blades yet. Â*But it's a sure thing.

I don't think it is something to be ashamed of. At least, I have broken a
few too. HSS, that's cheaper. :-))

My objective is to not break the lathe itself. But blades are
expendable.

The real problem is that when a blade breaks, whatever one is cutting
off is often ruined in the process.


I tried pushing harder, and it only shook harder. Â*Unlike with the 5/8"
bar.

If you had the same stickout (not enough for 4" to part off) there should be
no difference.

I was also having chatter problems with ordinary cutting bits, so
my suspicions turned to loose joints.

Oh! If you look at the bed in a cross section, you do have 3 (yes, 3 not
just 2) guides. Two on top (one being roof-shaped) and one on the rear
*bottom*. Here, a guide of the saddle is gripping downwards (can't express
better) and prevents the saddle's rear from lifting off of the bed. You
really have to bend over your lathe to see that guide. Got me? Check that
guide and adjust it.

You mean the hold-down plates and the carriage clamp plate. These are
under the ways and face up. The hold down plates are probably OK as
they are adjusted using shims, and so are pretty much user-proof. I do
use the carriage clamp when cutting off, and it does seat firmly. But I
will still look, just to be sure.


I bet many problems will go away when I get a better toolpost.

AXA AKA Multifix rulez! :-)

Ja! But they are pretty big. I'm leaning towards Aloris BXA.


Except that the compound and attached toolpost visibly tilted leftward
under cutoff loads, even when cutting the 5/8 bar.

Ouch! When parting off, move the top slide as much as possible to the
*right*. This way, it gets more/better support. But watch the jaws! EG

I did this, including getting too close to the chuck, but it didn't
help. Fixing the loose joints seems more direct.


He may be spinning the work too slowly.

No, he broke his next holder after my instruction and show and tell. But he
didn't blame me for that. :-)

Good. But you will need to watch him try cutoffs before you will be
able to figure out what is wrong.


Joe Gwinn