Circles with incorrect diameter

[Notselrach]

It does not matter whether I use Cut2d, or SimplyCam if I upload gcode to mach3 the resulting circle is not the correct size.  An 8" drawn in Cut2d is 8.5" after mach3 cuts it.  I am assuming that I have improper settings in mach3, but I don't know where to look.  The programs are not set to use any offsets.  help!

[RICH]

Post your gcode file created by the program.

The programs are not set to use any offsets.

But what size end mill is the program using to generate the code and what size end mill are you doing the cutting with?

You may want to also post your XML file for someone to have a look at.
RICH

[Notselrach]

I think the end mill choice is consistent in both.....1/8 round.  I will recheck that though......Thanks

[Hood]

If you command a move of 1 inch does it move that distance?
Hood

[Notselrach]

As soon as the ball game is over I will try that.  To try that test occurred to me too...BC

[Notselrach]

I tried a 4 inch line both vertical and horizontal and the actual length was 4.375 inches.  I took that percentage and applied it to an 8 inch circle and the result was the same.......Is this something to do with motor tuning?

[Hood]

Yes, your steps per unit are not correct. Either calculate them or use the utility on the Settings page(just above reset button on that page) to do it for you.
Hood