In article , John Dammeyer says...

Finally another major design flaw on the Gingery Lathe is in the
half-nut assembly. Once again, examine the tried and true products
out there and you'll find that the leadscrew is almost exactly
underneath the front ways. Gingery has it forward of the front ways
and that creates a twisting moment. Makes the carriage jam and harder
to move regardless of how well you've set it up.

For some reason, he also designed the half-nut to be offset from the
center of the carriage and cross slide leadscrew and that creates a
second twisting moment to the carriage. What I did was put the
half-nut shaft under the cross slide and had the lever project out to
the right. It could be to the left too for all it matters.

The AA product lathes all show this flaw as well, and the flawed
behavior you attribute to it. I think you are spot on with your
diagnosis.

The lead screw on those small machines is quite far out from the
bed, and the half nuts are at the extreme side of the apron. Which
gives rise to the twising and binding you talk about. Because
the AA machines have such tiny carriages this is a real problem
with them.

Jim

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