Cutting a spiral groove

Suggestions on how to cut a clean spiral groove. June 13, 2001

Question
A client has asked me to build a fixture for his artwork. This fixture will be a panel 5' x 5' x 6" deep. It needs to have a spiral groove approximately 1" wide x 1 1/2" deep cut into the face of the panel, starting in the center and rotating out to the edges. Any ideas on how to go about cutting a spiral groove cleanly?

Forum Responses
Find a shop with a point to point or CNC router. Try calling the tools sales places in your area--they should be able to help you locate a shop with one.

---

A CNC router is an absolutely great way to attack this. However, there was a time before CNC when people actually had to figure out ways to do these sorts of things without such equipment.

To do it yourself I'd suggest the following (try this on scrap first).

Take a 3" to 4" high cylinder of about 2" diameter (pvc pipe would work well). Secure it to the face of the board in the center of the spiral. Take a router and connect a cord from it to the spiral. As you move the router around the cylinder (I believe in a counter-clockwise direction and keeping the cord taut), the cord will wrap around the cylinder, continually shortening the distance between the router and the cylinder. Voila, a spiral groove.

You will of course have to experiment a bit to come up with the right cord length and cylinder diameter. But you should be able to make it happen.