31/32" X 5/16" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com High Quality Black Front /

High Quality Black Front / Black Back Patch Vintage BoltsandNuts

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Part Number DWRR41/64

Part Number: 100C900HCS8Y

Part Number DWTSH5/8-24

31/32" X 5/16" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com High Quality Black Front /Product 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