My Shapeoko 3 is cutting huge after update

[keysersoze]

I just updated to GRBL 1.1 and CM 4. I use CamBam to produce gcode. After the update, I tested one of my files, and my machine is cutting way bigger than it should. For example, a pocket which should be about 34mm wide is double what it should be (cutting about 70mm). I am still learning and am not sure how to fix this. Can anyone help me get my settings back to what they should be? Thanks for your help!

[WillAdams]

Do you have an older machine which has DIP switches for micro-stepping?

If so, they are set to 4x, and you had your steps / mm set to 20 --- Grbl 1.1 sets them to 40 since the new boards are hard-wired for 8x micro-stepping.

Power down and toggle the switches over to 8x (I'd move them back and forth a few times to ensure a good connection) and you should be good to go. If you wish, you could calibrate for belt stretch: https://docs.carbide3d.com/shapeoko-faq ... t-stretch/

[keysersoze]

WillAdams, thank you! I think that did the trick. I appreciate your help!

[GurneyHalleck]

So, if 40 steps = 1 mm, then 1 step = 1/40 mm = 0.025 mm (approx. 0.01 inches).

Does that set the Shapeoko 3 pixel at 0.025 mm on a side?

[WillAdams]

It's a microstep, but yes, but much motion is interpolated.