Versatile Center Gauge
I wanted to add accent dowel "dots" down the center of some slightly curved, tapered table legs. Sounds simple, but I nearly pulled my hair out trying to accurately find the center of these legs using a ruler! I was about to tick off the center of the leg every 1/4" to get the curve I wanted.
Forget it! I came up with a clever, self-centering gauge that works on any board, straight, tapered or curved.
I drilled a snug-fitting hole for a pencil in the middle of a 1/2" by 1/4" stick. Then I drilled two smaller holes for 10d nails an equal distance from the pencil hole. I spaced these holes so the distance between them was a little larger than the widest section of the leg.
I placed the gauge over the tapered leg and rotated it until the nails contacted the sides. I drew the center line of the board while keeping the nails against the side. Try it, it really works!
This is such a clever, useful accessory that I'd be tempted to make it using a little thicker stock, and maybe glue in short dowels instead of nails. The thicker stock would help register the pencil vertically. Another thing that works well for holding a pencil in a gauge like this is to install a threaded insert that's slightly smaller than the pencil's diameter. This way, the pencil is literally threaded in; there's no chance it will shift or slip out of the hole.