DentFix DF-1610 10.0 mm Spot Weld Drill Bit High Speed Steel Cobalt - Germany - The largest diameter High Speed Steel Cobalt (HSCO) spot-weld bit we offer. The twist is larger than the shank which is 8.0mm and has a flat spot on it to be tightened into our DF-15 Series Spot Weld Drills. This German made bit may be used with off brand spot weld drills. We also offer this bit with a Titanium heat resistant coating as part # DF-1610T. Our drill bits a specifically designed for the abuse of spot weld drilling. Flat ground for strength, centering nib to prevent walking. Our German made spot weld bits are available in 3 sizes, 6.5, 8.0 and 10.0 mm. These Cobalt high-speed steel mix bits are 45mm long and work with all brands of spot-weld drills. Titanium (gold color) is a heat resistant coating that extends drill life by about 50%.