This 1" radius marking jig was designed while installing 1/2" solid surface window sills with a bullnose edge.

After laying out dozens of sills, I wanted a quick, repeatable way to mark a consistent 1" radius without measuring every corner. Simply place the jig on the corner of the workpiece, trace the radius, and make your cut with a jigsaw, router, or hole saw.

The model is designed to print standing on its end, eliminating the need for supports while producing a clean, accurate radius.

I printed mine in PETG for added durability, but PLA works perfectly well for a simple layout and marking tool.

If you find this jig useful, I'd love to see your makes and hear your feedback!