Head-changeable hard alloy twist drill

Abstract

The invention discloses a head-changeable hard alloy twist drill which comprises a drill stem, a drill tip and a stopper screws, wherein the middle of the end face at the bottom of the drill tip is provided with a radial positioning block and two sides of the drill tip are provided with peripheral positioning grooves, the middle of the end face at the top of the drill stem is provided with a radial positioning groove and two sides of the drill stem are provided with peripheral positioning blocks, the drill stem is also provided with a threaded hole penetrating through the side wall of the radial positioning groove, the radial positioning block is arranged in the radial positioning groove, the peripheral positioning blocks are arranged in the peripheral positioning grooves, and the stopper screw is accommodated in the threaded hole and is in contact with the radial positioning block. The head-changeable hard alloy twist drill has the advantages of simple structure, convenient processing, accurate positioning, stability and reliability.

Description

technical field [0001] The present invention relates to a cutting tool for metal cutting, in particular to a cutting tool for drilling. Background technique [0002] At present, the commonly used drill bits are mostly in the form of one piece, that is, the shaft part, cutting edge, chip pocket, etc. of the drill bit are integrated, and they are all made of the same material. When the cutting edge part of the drill bit is damaged, the whole drill bit must be resharpened or replaced. Therefore, it is considered to make the cutting edge part and the drill bit shank into a separate detachable unit form, which is commonly referred to as a "replaceable head" by those of ordinary skill in the art. This replaceable head part can be easily replaced after wear and tear, so that the expensive cutter body can be used for a longer period of time, and the replaceable head part can be made of hard wear-resistant materials, such as cemented carbide, etc. The cutter body can be made of a m...

AI Technical Summary

Problems solved by technology

However, this tool also has some disadvantages, such as a slit at the joint between the drill shank and the replaceable head, the slit will expand during installation, and will fail due to fatigue after repeated use, and the clamping force on the replaceable head will be weakened. Poor stability; in addition, the convex part of the interchangeable head has a complicated structure and high manufacturing cost

[0004] German patent DE3230688A1 discloses a milling tool with an exchangeable head, the male part of the exchangeable head part being formed by a conical pin which can be moved into or out of a base, also of conical shape, which is placed in the Open at the front end of the body, the conical shape of the pin and the base means that the connection between the two must be formed as a special rotary lock, which is more complicated in production and makes the interchangeable head subdivisions aligned with the centerline of the tool body. The coaxial positioning between them becomes more difficult, which affects the machining accuracy

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