3/8" X 5/32" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Part Number KFD3F15/16

Part Number KFD3F15/16

Part Number: 56C550HCSSS

Part Number DWRRSP11/16

Part Number: Assortment Kit #1581269 Pieces - Coarse Thread

Part Number: 62C350ASBSS

3/8" X 5/32" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Part Number KFD3F15/16Product 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