Method and cutting insert for threading

Method for producing a thread in a rotary work piece, wherein a threading insert, including at least one cutting corner having a peripheral edge, creates the shape of the thread through a number of passes along the work piece during radial infeed, wherein the method comprises the following steps:

• providing the cutting corner with two cutting tips along its peripheral edge, each cutting tip including a radially, outwardly extending projection, said projections each extending a length in a radial, outward direction from a first imaginary line, said first imaginary line defined as a line drawn perpendicular to a bisector of adjacent flank edges of said cutting tips, wherein said lengths are different, each said cutting tip comprising a cutting edge, which is provided to form a thread top substantially between the cutting tips, wherein the total, projected length of the cutting edge is made less than two thread pitches,
• feeding the threading insert radially inwardly during simultaneous rotation of the work piece,
• passing the work piece a number of times with increased depth of infeed at each pass, wherein the cutting tips are brought to co-operate for cutting a top of a thread profile.