I’m experimenting with LC and made in Acad V.14 a circle 1-1/16” OD

I import the dxf file to LC, selected a 1/4" bit and got the g-code on Mach

When the cut was done, the circle OD was 1.29”

Am I doing something wrong?

If you just selected that circle in LC and didn't do any offsets then the pathing would be along that circle and the od cut would be
1.3125". Now if it only cut 1.29", then you could have done something wrong in LC or you have someting set wrong in Mach.

RICH

In AutoCAD, you need to make the circle 1-1/16 minus the tool diameter, or 13/16". Normally, the lines and circles you draw in AutoCAD are the center of the tool, unless you use offsets in your code, or let your CAM program do the offsets.

1.3125 is my circle OD + the tool diameter so as Gerry is saying I will redraw the circle minus the tool diameter

Good to know this, thank you both

So in your original question, are you asking why it's 1.29 instead of 1.3125?

In my original question the 1.29" was wrong (I didn't measure correctly). I check it again and it is 1.3125"

I try to press fit a bearing with an OD of 1-1/8" and I'm experimenting that 1st on MDF and after it will be done in Aluminum

I just cut 3 circles, 13/16", 14/16" and 15/16". The bearing fitted just tight, as I wanted on the 14/16" circle

Of course in the Aluminum it may be different but I will experiment and see the results 

Nicolas,
Think the numbers in reply #5 are somewhat mixed up.

RICH

Sorry RICH, the numbers on reply #5 refer to the circles I made in ACAD minus the 1/4" tool diameter.

So the 13/16" circle has a 1.0625" OD
the 14/16" circle has a 1.125" OD
the 15/16" circle has a 1.18" OD