Step Drill Bit Set Set 1/4"-3/4" 1/8"-1/2" 3/16"-1/2" HSS 4241 Titanium Coated Straight Flutes Hex Shank for Metal Wood Plastic Dark Gray The screw holes are designed

The screw holes are designed as countersunk holes

Arm Opens:90 degree

Inner  Diameter: 41

clear threads with no burrs

Total Length: 420mm / 16

Step Drill Bit Set Set 1/4"-3/4" 1/8"-1/2" 3/16"-1/2" HSS 4241 Titanium Coated Straight Flutes Hex Shank for Metal Wood Plastic Dark Gray The screw holes are designedFeatures: Laser marking makes the size more clear; Used on electric drills and drill presses; Double cutting edges design enables a faster and smoother cutting; Hexagonal shank prevents slip in electric drills and presses chuck; X type openings design to facilitate the removal of cutting waste when drilling; The sharpness and titanium coating ensure easily cut through most metal, aluminum, plastic, wood and other materials with ease; Specifications: