1-1/16" X 5/16" Pilot Hole HSS Taper Shank Counterbore Shopify Collective Part Number: BIT-DWTMHX16X1

Part Number: BIT-DWTMHX16X1

Part Number D/ARSD1-7/16

Each slot in the rack is made to fit a specific L-key size

Part Number: EZ-30870

Flute Length: 2-5/8"

1-1/16" X 5/16" Pilot Hole HSS Taper Shank Counterbore Shopify Collective Part Number: BIT-DWTMHX16X1Product 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