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" (8~38mm)  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" (50mm) tall, including the height of a bushing.

Made from durable polycarbonate, it comes with 3mm, 5mm and 6mm hardened steel bushings.