In article ,
Nick Mueller wrote:

Joseph Gwinn wrote:

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

That's part of the learning process. No pain, no gain.

True enough.


You mean the hold-down plates and the carriage clamp plate.

If the hold-down plates are on the rear, yes. The carriage clamp is on the
front. I mean the similar setup on the rear.
I suspect that your carriage's rear is lifting off. Why?
With a small diameter, the cutting force is projecting within the two guides
of the bed. With a big diameter, the force is moving outside of the guide
and thus tilting your carriage (lifting the rear).

I'm not sure that this could be the mechanism, because even the larger
bar is well centered between the two rails of the way. Nor can I
imagine the person that allowed the dovetails to become so loose
concerning themselves with something like the hold-down plate. In fact,
I doubt that they could find such a plate in broad daylight.

But it's easy to check that the hold-down plates are correct.


I do use the carriage clamp when cutting off, and it does seat
firmly.

What I do with deep(er) cuts is to initially clamp the carriage and later
(after 1/3 or such) loosen it.

OK. By the way, the carriage clamp plate works on the front bed way
rail, and so would not much help if the back hold-down plate were loose.


You also have to pay attention that the blade is dead at 90° to the spindle.
An easy way to check this is to move the carriage to the left until the
blade's side touches the chuck's face. No, not with the lathe running G.
Then you see how well it aligns or not.

I've been using a little square between the bar to be cut off and the
blade. The 5/8 rod was in a collet, with no easy reference surface.

Hmm. Another difference in rigidity. The 5/8 rod was in a collet,
while the 1.35" rod was in a 3-jaw scroll chuck.


Ja! Â*But they [MultiFix] are pretty big. Â*I'm leaning towards Aloris BXA.

There's one size below size "A". It's "Aa". But you have to check tool
height.

I'm sure that there is a recommended size for any given lathe. The BXA
is what Aloris recommends for the 5914.


I have similar ones to the Aloris on my small lathe. They aren't good with
repeatability. If you remove it and reinsert it, it is on a slightly
different place.
The Multifix really has an repeatability of 1/100mm. I tried this.

I believe it, given the inherent averaging from clamping two zigzag
surfaces together. How bad was the Aloris clone repeatability?


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

Will happen when I help him install his VFD. But first, he has to help me
bring down my replacement lathe.
No, I didn't break it! It simply was well out of specs, so I finally got a
new one yesterday.

You wore it out? I bought mine pre-worn.

Joe Gwinn