Based on a suggestion from cabinetmaker Stephen Shepherd for a jig that could drill chair spindles, this centering jig has a large bearing surface for accuracy, with sighting marks for easy visual alignment. Used for end-drilling round stock 5/16" to 1 1/2" in diameter, it also permits drilling of spheres and has a V-notch for drilling into the side of a cylinder or the edge of dimensioned stock.
As a side benefit, the conical shape helps catch dust when drilling overhead. The jig stands 2" tall, including the height of a bushing.
Made from durable polycarbonate, it comes with 1/8", 3/16" and 1/4" hardened steel bushings. Metric bushings are available separately.