15/16" X 1/4" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Diameter/Pitch: 5/16"-18

Diameter/Pitch: 5/16"-18

Flute Length 92

Part Number: 75X450DPAPL

Part Number DWRRTP8

Flute Length 106

15/16" X 1/4" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Diameter/Pitch: 5/16"-18Product 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