Custom Diameter Bit

A few years ago, I was installing some balusters that the customer had picked up from a salvage yard for his stairway. I went to my local lumber supplier and bought some 3/4″ dowels to insert into the bottom of each baluster so we could glue them into holes in the stair treads. When I drilled a 3/4″ hole in the bottom of one of the balusters with my paddle-bit, the dowel fit was sloppy at best. Both dowels were definitely a bit narrower than 3/4″. My next size bit was 11/16″ and that was too small. So I clamped my 3/4″ paddle bit in a vise and filed each side of the bit, then tried some test holes.

After a few tries and being careful to file the same amount off each side of the bit, the bit gave me a perfectly sized hole for a snug dowel fit. You can also file the sides of the paddle bits with the sharply pointed side cutters using the same method. Here’s another twist on the same idea: While fitting a hole for a tapered tenoned handle for a wooden mallet that I made on the lathe, I ground a paddle bit to a taper and drilled the bottom of the mallet head to accept the handle. It worked perfectly.