Saturday, February 26, 2011
Update: Wooden Chalkboard Compass
The compass prototype needed an improvement on its original non-slip tip, which was the eraser end of a "My First Ticonderoga" pencil. After a little digging at the local hardware store I came out with some rubber stoppers that I thought might work.
To fit the compass, the stopper had to be screwed to a short section of 3/8" dowel. I drilled a countersink just larger than the screw head, and then a smaller hole just larger than the shank all the way through the stopper. In the dowel, I drilled a pilot hole a little smaller than the shank.
I was worried the screw might split the dowel, but I guess I got the sizes right, as everything worked just like it should. Here's a picture of the final product.
You can also see the plowed guide channel for the wedge that tightens the chalk side of the compass. The dowel with the rubber tip is just a friction fit.
I tried it out last week and it works much better. It will still slip if there is a lot of chalk on the board. Or if my technique is sloppy...