Is easel unit conversion causing my issue?

Hello Everyone,
Its been a while. I haven’t used easel in a long time but im trying to do a project with some kids and of course i look like an idiot when things don’t turn out right.

I am cutting basic shapes squares and rectangles at a precise size. Im doing the dimensions in mm. when everything is carved out all the dimensions are off by about 1 mm short. I checked my travel it is perfect.

What im wondering is im using a 1/8 bit but when i select that in the bit library it says 1/8th but then it i hit the toggle to mm is says .13mm width. 1/8th should be 3.175mm. Could this be causing my lost mm? if not any other ideas? the machine cuts these tolerances perfect using other programs but i want the kids to be able to use easel.


My first guess was going to be that you’re selecting either “inside” or “centered/on edge” (can’t remeber exact wording, on phone) as opposed to “outside” for your outline cut, but those would produce a shape that’s off by either one or two times the bit diameter.

Have you calibrated your X and Y steps/mm ($100 amd $101 parameters) recently? Are you sure your jogs are moving exactly the right distances?

Does your machine have set screws on the stepper motor pulleys? If so, check them all for tightness (in your case, especially the X and Y).

First thing I checked too was how I set it to cut. It’s a pocket not a out line. Steps per mm are perfect across full travel. Checked the bit it’s the right size. It’s so weird.

Can you export the gcode and post it here? (163.1 KB)

According to your gcode, with a .125" end mill, the pocket I identified should be 48mm wide. That sound right?

Yea should be 48. Just measured it cut 47

Gcode has it at 48. What’s the Y dimension (measured)? The gcode has it at 22mm.


Where is that in the gcode? I want to make some changes and see what happens

Designed as 22mm?

I use this previewer.
Click on the corners, get the coordinates, and do some math. Don’t forget that the path is the center of the bit.

You should atleast edit the mm value to the correct one, 3.175mm in this case (Easel may round up a little)
1/8" = 0.125inch => Easel keep this value when changing from inch to mm (displayed as .13)

  • Your calibration is good
  • Measure the actual cut width of your 1/8" tool, the 1/8" value is nominal and dont reflect router run-out, deflection and actual diameter variances.
  • If a pocket then still is undersized it is due to tool and machine deflection/backlash.

Test a pocket of 50x50mm and another one 100x100mm, is the deviation the same or does it increase also?

Within Easel:
If it remain constant => system deflection
If it increase => step/mm issue

This is what makes this situation unusual.

I cut some pockets with aspire just to make sure nothing went out of wack and they were perfect dimensions.

When I was designing in easel I went back and forth between metric and imperial a lot. Somewhere along the way something got off.

I’m gonna do some tests to see if I can replicate the issue.

Again, the gcode you shared shows the correct dimensions. It shouldn’t matter what software generated the code.

yea but the one i sent you was after i was playing around with it and making changes to try to figure out what was wrong.

So everything’s working now?

EDIT: I just tried to replicate what you saw. When you change the BIT unit from inches to mm or vice versa, Easel does not convert the measurement. You’re probably seeing a difference in toolpaths of a machine “thinking” it has a 0.13mm bit when you actually have a 0.125in bit. That said, I think you’d see it a couple mm bigger, not smaller. Anyway, instead of guessing, I’ll let @JoeSimone tell us what he noticed.