Using Pilot Drill Bits
Pilot drill bits are any bit with a self-guiding shaft on the tip designed to follow a pre-existing hole. In this case the pre-existing hole in these arbors is 1/4″ in diameter. Pilot drill bits can be bought from machine tool suppliers, but can be made. We build our own pilot bits from wood boring spade bits of all sizes by attaching an aluminum 1/4″ outside diameter tube to the tip with epoxy glue.
Preparing For a Strong Bond
To make for a strong bond, the sharp tip of the spade bit must be scored and reshaped with a Dremel tool, then we secure a 1″ piece of the 1/4″ aluminum tube over the scored tip with paste epoxy. We take special care to keep the tube centered by eye or with our machined pilot bit drying rig.
Drilling Out the Arbor
Once the pilot bit is dry, we drill out the center of the arbor, secured in a reel seat, to a diameter just smaller than the blank. The pilot bit will guide itself through the center of the arbor without deviation with a hand drill. We then touch up the drilled hole with a tapered abrasive reamer to match the desired taper of the rod blank.