There’s a few 3D printable corner cut jigs out there. I designed my own for three main reasons:

  1. There’s a little ruler on the side to mark the width of the fold-over section of the cloth
  2. It’s parametric (using OpenSCAD), so you can customize various sizes (spacing from corner, various thicknesses, size of ruler, etc.)
  3. I like to model stuff myself because it’s fun.

makerworld.com/…/2000894-corner-cut-jig-with-rule…

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