METHOD FOR CUTTING MULTI-START INTERNAL THREAD Russian patent published in 2004 - IPC

FIELD: machine engineering, working of materials.

SUBSTANCE: method comprises steps of forming thread profile at each preliminary pass and at sizing pass by means of tap performing helical motion relative to worked part; in order to enhance accuracy and strength of thread profile, making it simultaneously by plastic deforming and by cutting and alternating said operations. When thread profile is made by cutting at preliminary pass, its value may be less than that made during preliminary pass by plastic deforming. When thread profile is formed at sizing pass, change of thread profile by plastic deforming is performed by less value than at cutting.

EFFECT: improved accuracy and strength of thread profile.

2 cl