Brownells High-Speed Steel Lathe Cutting Kit 1/4 in Turning Tools

a 'Tooling kits include hardened steel toolholders and high speed steel inserts for turning, threading, profiling, and cut-off work. Inserts are T-15 High Speed Steel (HSS) hardened to Rc 65-67, then finish ground on all sides. They deliver excellent slow speed performance, precision interrupted cuts, and a smooth finish on stainless steel, Inconel, Monel, exotic metals, and plastics. Square shank toolholders and boring bars are CNC machined from 4140/4142 steel bar stock, hardened to Rc 48-50, and then black oxide coated to resist corrosion. Includes five A 1/4" square toolholders and six inserts, including one spare. Mfg: Brownells SPECS: Toolholders - 4140/4142 steel, Rc 48-50, black oxide finish. .250" square, 3.5" OAL shanks. Inserts - six T-15 HSS TPMW-1.8-1.5-1, Rc 65-67, finish ground on all surfaces. 11Adeg positive, 218 IC, .093 thick, .100 hole, 130 top opening @ 60Adeg .015 radius.