Re: 7.5 HP Lathe on a 10 HP idler?

On 2009-05-16, Ignoramus26671 <ignoramus26671@xxxxxxxxxxxxxxxxxxxx> wrote:
On 2009-05-16, DoN. Nichols <dnichols@xxxxxxxxxxx> wrote:
The *real* test is to put a heavy chuck (e.g. the typically
larger 4-jaw) on the spindle, close the jaws on something so they don't
spin loose, set for the highest spindle speed (within the safety range
of that chuck, of course), start it at that setting, and once it is up
to speed, reverse it and see what happens. The only more sever test
would be to have a maximum diameter workpiece (which will clear the
cross-slide) the length of the lathe between centers -- or perhaps
reversed jaws and the largest diameter workpiece which is short enough
to not walk out of the jaws without tailstock support. :-)

So, DoN, do you think that with the chuck heavy enough and RPM high
enough, plug reversing the lathe would actually reverse the idler?

Yes, I do. Of course, that depends in part on the relative
horsepower ratings of the idler motor and the lathe's own motor. I have
read here postings by people who have experienced that with equal
horsepower on each. And *that* might be something which could be
improved somewhat by a flywheel on the idler motor -- but expect the
housing to jump around during the reversal. :-)

Tuning and balancing capacitors might change the threshold at
which this reversal happens in that they will be applying a bit of
rotational bias -- but with equal sized or smaller idlers, you still
will have the idler reverse at some set of parameters.

(I believe that it is true, based on general symmetry considerations).

Indeed so.

Enjoy,
DoN.

--
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