15/32x1/8 Pilots for Counterbore
If, on the other hand, the hole is enlarged to a considerable depth, it is designated as counterboring. Counterboring is the enlargement of a portion of a hole that has previously been formed. These counterbores are made of two-piece construction, having an integral shank and counterbore-cutter, and a pilot that is interchangable, which provides flexibility in the use of the tool..