Hi Guys, newbie here so please be gentle!  When I did my first test, it should have cut and 83mm disc, but it cut at about 130mm !  Used Easel to create the G-Gode and the size was ok. Move the cutter head 100mm on screen, and the bit moved 100mm actual. SO not sure where to look for a solution. Can I just calculate the % difference and reduce the scale function in MACH 3 to get the correct final output size, or am I doing something wrong ?  Thanks, Tim

You are doing something wrong (probably in Easel).

To rule out one possibility use the Axis Calibration feature (Settings screen) to check that you have your Steps per Unit set correctly for each axis.

Tweakie.

Hi Tweakie, thanks for replying.

The size of 83mm in easel is correct as to what I have drawn. Might try working in inches !.   Are there different Gcodes (50 / 51) that might need adding?

When I measured the actual movement of the router bit against a rule, it looks spot on. Guess I will run a few experiments, and see if it is easel of Mach 3 casuing the issue.

Thanks, Tim

Can you put the code you used up so we can see what that is like, what cutter size was used.

The code for an 83mm circle with a 6mm cutter on the outside of the circle would be something like this

%
G21 G40 G80
G54 G00 G90 X44.5 Y0 Z25. S10000 M3
Z1.
G01 Z-2. F500.
G03 I-44.5 F1000.
G00 Z25.
M30
%