Home-made circle cutter jig for routerEvery once in a while I need to cut a curve in a sheet of timber. Typically I will do this with my router attached to a simple beam compass (see photo, left), but it can also be done by attaching the sheet to an armature for cutting over a fixed (table) router. In either case I typically know the width and depth of the curve I'm after, but not the length of the armature (i.e. the distance from the pivot to the cutting head).

I wrote the following to do that calculation...


units (e.g. mm)
units (e.g. mm)
Curve radius (green lines = grey+blue line): 100.0 units (e.g. mm)

Another of my calculators you might find useful: Circle/Cone Calculator