The range of Adjustable Hand Reamers are extremely useful precision tools for any engineering or auto-repair shop. Just 16 sizes cover diameters ranging from 3/8" - 2.7/32" (9.5 mm - 56.35 mm). These are ideal for use on steel or nonferrous metals. The reamer blades are made from high speed steel, accurately hardened 60 - 64 HRC and relief ground. Each adjustable reamer has a chamfer or lead on the front end of diameter 0.004" - 0.019" according to size, which helps to make a quick start in reaming operation. Reamers expand by loosening one adjusting nut and tightening the other .