Busch 4203S 2 Groove Carbide Twist Drills on 3/32" Shanks 0.7mm to 1.60mm

2 Groove-Recommended for Hard Materials like Steel, Platinum, Titanium & Hard Metal Alloys of Gold and Silver-Outstanding Service Life Choose from 10 sizes: BAU128.427  0.70mm BAU128.428  0.80mm BAU128.429  0.90mm BAU128.430  1.00mm BAU128.431  1.10mm BAU128.432  1.20mm BAU128.433  1.30mm BAU128.434  1.40mm BAU128.435  1.50mm BAU128.436  1.60mm Sold by the Piece The 2 groove design of these special Busch 4203S 3/32 inch mounted carbide twist drills helps expel more material from the hole making these drills perform better and last longer when cutting hard metals. Carbide drills will outlast high speed steel or standard Tungsten Carbide when used for drilling in jewelry metals. You can even use these drills on mild steel. Using a coolant increases the life span, and these drills will last the longest when used in a drill press, as like any drill, breakage will occur with excess leverage or canting. If using by free-hand, the recommended speed is 5,00