rlincolnh wrote:


I have a new Chinese 14x40 gearhead lathe, and it seems to be a
reasonably solid unit although I'm still just finding out what I can do
with it.
[...]

So here's the question; How is it that I can produce a perfectly
circular result, yet which appears to be off-centre from the spindle
axis? For the life of me I can't visualize the conditions that would
lead to this.

A possibility - the drive gear is pressing against the spindle-mounted gear
while under power at 2000 rpm, and moving the spindle's axis position. At
low speed a different gear is engaged, and turning by hand there is no real
force.


As I said, only a possibility.


btw I find your actual measurements slightly unrealistic. Are you sure you
did them right?

--
Peter Fairbrother