Abstract: An object of improvement is a threading tool that includes multiple cutting edges 3-1 to 3-n (where n is 5 in the drawings) disposed side by side and that performs threading successively using the multiple cutting edges to form a thread. At least one of the cutting edges of the tool except a finishing edge 3-5 is deviated in an opposite-to-feed-direction direction of the tool (may instead be the feed direction).

Abstract: A coated tool includes a base material and a wear-resistant coating film formed on the base material. The composition of the wear-resistant coating film is expressed as (Ti.sub.x,Al.sub.y,V.sub.z)(C.sub.u,N.sub.v,O.sub.w). Relations x+y+z=1, u+v+w=1, 0.2<x<1, 0.ltoreq.y<0.8, 0.02.ltoreq.z<0.6, 0.ltoreq.u<0.7, 0.3<v.ltoreq.1 and 0.ltoreq.w<0.5 hold between x, y, z, u, v and w. The thickness of the wear-resistant coating film is at least 0.5 .mu.m and not more than 15 .mu.m. A coated cutting tool in particular includes a base material consisting of cemented carbide and a wear-resistant coating film formed on the surface of the base material.

Abstract: An indexable insert with a chip breaker configured such that chips produced under various cutting conditions from rough cutting to finish cutting can be disposed of in an optimum way. Protrusions are provided in a chip breaker groove to extend from a central land toward the respective corners of the insert. Each protrusion has a breaker wall which is concave and curved such that chips produced always collide against the breaker wall at an angle of 10.degree.-40.degree. so that the chips are curled helically with a helix angle of 10.degree.-40.degree. and broken into small pieces reliably.