I had to scribe a board to fit against an old brick wall last week, but I didn’t have my scribing compass with me. However, I did have my drill bits and some assorted hardware. The drawing below shows how I used the parts on hand to make a compass. I started with a couple of old spade bits, which already had 9/32-in. holes in them. Then I scrounged a couple of washers, a lock washer and a 6/32-in. screw and nut from a junction box. I ran the screw through the holes in the bits, sandwiching the washers between the blades. Voila — tensioned calipers. I taped a pencil to the shorter of the two drill shafts, creating a crude but effective compass that worked just fine.
Rob Arthur, Lyndhurst, None