| 摘要 |
A roller for rolling tool-joint threads of pipe drills additionally comprises an upper deforming part, and lateral surfaces are formed by truncation of a cylinder by two planes located at an angle to the section that passes perpendicular to the axis of the cylinder, which is defined as, where- angle formed between lateral conic surfaces and lateral surfaces of the vees of thread, and the upper and lower deforming parts of the roller are made with a rounding for an angle equal to the radius of curvature of thread vees. |
