2-1/4" X 1/2" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Part Number DWDA/CX1229/64

Part Number DWDA/CX1229/64

Drill Size: 1-7/64"

3/8 inch to 1/4 inch drive reducer

Part Number D/ASTCO31/64

2-1/4" X 1/2" Pilot Hole HSS Straight Shank Counterbore BoltsandNuts.com Part Number DWDA/CX1229/64Product 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