Why do my pocket corners look like this?

I have an issue where my pocket cuts have an odd shape in the corners.

You can see it in the photo, bottom left corner shows this the most. Any suggestions on fixing. Is this a belt tension issue? Play in the Z? Any suggestions welcome :slight_smile:

I’d guess either an incorrect/imprecise bit diameter or poor belt tension… or stepper sprocket slipping (tighten the set screws).

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With the machine on, see if you can easily move the carriage along and and/or y. If it moves a small amount (1/8" or so) without any resistance that might indicate a loose set screw on the motor shaft pulley.

One possibility is simply a matter of the toolpaths β€” try leaving a roughing clearance and making a final finishing pass.

Electro-mechanically check:

  • pulley set screws: http://docs.carbide3d.com/shapeoko-faq/shapeoko-3-how-to-check-the-pulley-set-screws/
  • V-wheels β€” make certain that the eccentrics have been tightened so as to hold the gantry/carriages in alignment
  • belt tension β€” think guitar string tight for the Z-axis, a bit less for the X, and only slightly less (and an equal tension) for the two Y-axis belts β€” careful not to bend the motor shafts though.

Thank you all for the help and suggestions I will try all of this over the weekend. I really appreciate the help!