Dowel Gauge

Doweling can turn dicey when the dowels don't quite measure up to their stated diameter—or the hole you drill is too shallow or too deep. The solution? Build our 4-in-1 dowel gauge. With it you can double-check these measurements before you assemble a project.

Here are the four features this handy helper provides:

1. The dowel-sizing gauge on the face of the block offers three holes with standard dowel diameters plus holes that measure 1/64" larger and smaller than the standard diameters. Check the fit of your dowels in these holes, then you can select the appropriate drill bit if your dowel is just a hair too big or too little.

2. When you want to drill a hole to a precise depth, use the hole-depth gauge. Just insert your drill bit in the appropriate hole, and mark the depth on the shank of the bit with a piece of tape.

3. The dowel-hole depth gauge gives you two holes that measure one-half the length of two standard dowel lengths—1-1/2" and 2"—plus 1/16". Use these holes to mark the depth on your drill bit. By drilling your dowel holes 1/16" deeper, you give excess glue a place to escape and your dowel won't protrude too far from its hole.

4. At the rear of the block, the V-slot helps keep your drill bit plumb. Just place the bit on the workpiece, push the slot up to the bit, and tilt the bit until it fits snugly in the corner of the slot.

To build the gauge, use a piece of kiln-dried hardwood. This will help minimize any humidity-related swelling and shrinking of the wood.