Screw tap used for stretching threads

Abstract

The invention relates to a screw tap used for stretching threads. The screw tap comprises a screw tap body, a thread cutting part is arranged at the front end of the screw tap body, a clamping part is arranged at the tail end of the screw tap body, thread teeth are formed on the thread cutting part, an extruding part is arranged between the thread cutting part and the clamping part, the thread cutting part is of a conical structure, the extruding part is of a cylindrical structure, the diameter of the bottom end of the thread cutting part is equal to that of the extruding part, oil grooves extending from the top end of the thread cutting part to the extruding part are formed and arranged parallel to the axial direction of the screw tap body, and the four oil grooves are evenly distributed in the axial direction of the screw tap body. Compared with the prior art, aiming at the problems that a bottom hole of a workpiece is small, and a thread pitch of the workpiece is large, the mode of the screw tap is improved into front-end cutting and rear-end extruding, the problem that when a pure cutting screw tap is used, strength is low is well solved, and the service life of the screw tap is greatly prolonged.

Description

technical field [0001] The invention relates to a screw tap, in particular to a screw tap for stretching threads. Background technique [0002] In the case of a large number of welding nuts currently used, the original installation mode has been completely changed, and the purpose of quickly installing the fastening plate can be achieved without pre-welding nuts on the substrate. [0003] Existing taps such as figure 1 As shown, it includes a tap main body 1. On the side of the threaded part of the front end of the tap main body 1, there are four cutting grooves 2 along the axial direction. The cross section of the cutting groove 2 is rectangular, and the inner edge of the rectangle is perpendicular to the radial direction. The sides are parallel to the radial direction. The function of the cutting groove is to accommodate the coolant to reduce the cutting resistance and wash away the waste. However, the rectangular cutting grooves of the existing taps contain less coolin...

AI Technical Summary

Problems solved by technology

[0005] The above-mentioned patents have improved the structure of the cutting groove. The starting point is to improve the cooling and lubrication functions during machining, and have a strengthening effect on cutting. However, because it only has the cutting function, its functionality is relatively simple.

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