A unibit is a pyramid-shaped bit that has different diameters. It looks like stair steps or discs stacked on top of each other. The unibit has a greater diameter at the bottom and becomes narrower ...

The drill bit inside the housing is, therefore, centered in the hinge hole, ... Irwin UniBit 10234 3/16-inch to 7/8-inch Step Drill. $37 at Amazon. $67 $31 at Walmart $45 at Lowe's.

Step drill bits, such as the venerable Unibit, can drill several hole sizes in a single operation.These single-flute bits are specially designed for thin materials, and feature steps of ...