Detailed introduction to Screw Countersinks:
Screw CountersinksLarge 1/4" gold socket head screw - the drill bit will not slip.3/8" or 1/2" diameter counterbore.Combination countersink and/or counterbore for standard wood plugs.Standard hex shank fits all power bit quick change chucks.Alloy steel and thru hardened for long life - can be resharpened.Drill bits are adjustable for different length screws.82 degree countersink angle.Drill bits are replaceable with standard round drill bits.