OK, sounds good. I'll give it a try tomorrow AM.  Thanks for the idea.
Wayne

Well I tried the code, ran it for 1/2 hr.  Checked it  during and at the end, it came within .001 inch of starting position every time.    Truly  confusing how it can be so deadly accurate, but my circles are elongated.  ??

Thanks for the test, I am open to ANY other ideas or suggestions.  I use this in my Welding and Fabrication business so it is very important to me to get it right.

Well... I think I need to see what we are working with. Do you have a Pic of the machine and what you are using for a drive on the machine? Also can you tell me if the rate that you go around the circle changes the amount of ovaling  that you have?

Well the only thing I can think of - and it's a bit of a long shot, is that the X and Y axes aren't at 90 degrees to each other. So a square would be machined into a losenge shape and a circle would be made into an oval. Straight line movement would remain accurate though. Might be worth checking. All the best, Martin.

We tested the mill here and we are not seeing the problem that you are having... Could you please check that the axis is square.
Thanks
Brian

I had the flat spot on circles for a while now. I didn't think that if X & Y axis was a little off square it wouldn't matter. After trying everything else I tested the Square & it was off just a little, Squared it up & that's all it took.
Wouldn't think a small thing like that could cause so much of a problem.

Thanks
Ron

One of the things I picked up on ebay is a nice granite angle plate that is 9"x9"x9". I just set it on the table butted up against the axis way ( stationary table design) and I can check all 3 axis with a dial indicator in just a couple minutes. Handy for When I crash!