Don Foreman wrote in
:

I have a T-shaped parting tool in an Aloris BXA7 holder that won't cut
straight. It drifts to one side or the other as the cut progresses.
The bit is .063" at the bottom, .094 at the top, .686 high. As far
as I can tell the cutting edge is ground square (parallel to the
lathe axis), the bit is vertical in the holder to within a thou or
two, and the bit was square with the workpiece at center height.

I have a thinner tapered parting bit that does cut straight. It's
.0625 at the top, .043 at the bottom, .687 high.

The lathe is a 15x50 gearhead, no problem with stiffness or rigidity.

I'm not exactly a newbie with a lathe, but this one has me puzzled.

Any suggestions about what's going on here, please?

Thanks!

Don Foreman


Don,
If there is any perceptable difference in the edge radii on the tool, it
will pull. You may not *think* you can flex the tool holder...but you
can.
Cutting tools, especially grooving type tools, will follow physics and
take the least resistive path. If one corner is machining more freely
than the other, the tool will drift to that side.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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