25/32" X 3/16" HSS Aircraft Counterbore 1/4" Shank BoltsandNuts.com Used on concave and convex

Used on concave and convex as well as flat surfaces

Part Number: BIT-DMS71-1611

Part Number DMOD26

Part Number DWC5-530-375

25/32" X 3/16" HSS Aircraft Counterbore 1/4" Shank BoltsandNuts.com Used on concave and convexProduct 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