BR-8SQ : 70850 Description: Super Premium Bolt Remover & Left Hand Spiral Jobber Length Drill Set 8 Pieces Type: 240-AL & 421-UB Sizes: Drills: 5/32, 3/16, 1/4 & 5/16 Bolt Removers: EX 2, 3, 4 & 5 Fast and easy stud removal. Left hand spiral drills often eliminate the need for bolt and screw extractors. Drill may loosen bolt stud with counter clockwise rotation. 135° split point drill will cut harder metals than a 118° point drill. Most broken studs are work hardened during the breaking process. Drills: Special Hi-Molybdenum tool steel. 135° split point for fast penetration and accurate starting without a center punch. Precision ground point, body, clearance and drill diameter for the ultimate in accuracy and performance. Body and clearance are gold surface treated for maximum lubricity. Drills are heat treated at 2185° F and then nitro-carburize finished at 950° F to be measurably harder than high speed steel. Space aged nitro-carburized steel withstands substantially higher drilling temperatures while maintaining sharpness. Recommended for use in work hardening grades of stainless steel and other hard metal drilling applications. Bolt Removers: The square shape of these extractors gives the tools the ability to remove broken bolts, screws and pipes with minimum deformation of the broken part. The forged construction imparts an extra degree of toughness, which reduces extractor breakage. To remove the broken threaded part: Drill a hole in the end of the broken part (left hand spiral heavy duty drills are recommended for this drilling operation), insert extractor and turn counter clockwise using a wrench on the exposed end of the extractor. The broken part should unscrew without damage to the threads. These forged extractors will not chew up or expand the object being removed..