11/16" X 3/16" Pilot Hole HSS Straight Shank Counterbore Quantity:1 similar to a 12-point box

similar to a 12-point box end wrench

Size 7/16"-12

Part Number: 50D650CABZ/TAPKING

Part Number: 100C600SHCSABO/USA

and square

11/16" X 3/16" Pilot Hole HSS Straight Shank Counterbore Quantity:1 similar to a 12-point boxProduct Description Counterboring is the enlargement of a portion of a hole that has previously been formed. If the counterbored portion is shallow (1 8" or less), the operations is usually known as spot facing; for example, a flat seat for a bolt head or nut. If, on the other hand, the hole is enlarged to a considerable depth, it is designated as counterboring. These counterbores are made of two piece construction, having an integral shank and