Edit: I just facepalmed myself, on this test, I used a .25 bit but I think I used a .125" bit in Vcarve.
I just ran down and did another test square and it was .002" off on the X and Y. That more like it.
I’ve had my shapeoko for a little over a year. I did some test shapes when I first got the machine and pretty accurate but now its off. I am thinking its due to belt stretch but for some reason when it gets to the numbers and math I go brain dead.
So I made a series of boxes(see picture)
On the left side of the picture I made a 4" box and a 3" box inside of it. I did a pocket between the two boxes.
As you can see the pocket was “larger” than it was supposed to be on the outside and the inside.
So next I made some boxes and did an outside cut of some squares, I will just concentrate on the outer one.
Drawn size: set to cut on outside of line
X=3.8770" (diff: -.123)
Y=3.8815" (diff: -.1185)
Now hold my hand and walk me through this.
in case this matters, I’m using V-carve Pro and i used a .25 endmill