If you have a metal ruler, you can use this design to make it into a large compass. I used a 40" ruler from Harbor Freight. On end is pinned to the work service. Then, the movable part is adjusted to be the radius of the circle. Then, insert a pencil in the hole in the movable part and draw your circle.

This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/3OMXow3RsqJ