Die, if the tap is a tool for tapping internal threads, then the die is a tool for tapping external threads. Dies can be distinguished by their appearance: round, square, and hexagonal. At present, the dies circulating in China are all round. As for square extraction and hexagonal dies, they are very rare and rarely available on the market.
When processing round dies, they are in a half-cutting and half-extrusion state. The inner diameter and middle diameter of the die are the cutting part, especially the inner diameter of the die has to withstand a large cutting force, so it must have a certain strength and cutting ability. Considering that there should be a certain gap between the screw cut by the die and the screw hole, and considering the amount of wear, when designing the die, the inner diameter and middle diameter should be smaller than the nominal size of the inner diameter and middle diameter of the thread.
The classification of die materials is basically the same as that of taps
1. Metric coarse thread
2. Metric fine thread
3. BSW thread
4. BSF thread
5. G pipe thread
6. UNEF thread
7. EN thread
8. NPT thread
9. UNC thread
The material of die is generally HSS high-speed steel, and the tool used with die is called die holder, which is a manual rotating tool for holding die. The size can be adjusted to a certain extent, and the die within the fixed specification range is used for processing.
According to daily work needs, different thread specifications require more than one tap or die. One tap or one die, their specifications are fixed and cannot be adjusted. In order to facilitate use, tap and die sets appear. According to the requirements, the tap and die set is a set of combined tools consisting of several or more taps, dies and tap wrench die holders.
what different of hand tap and machine tap?
Another major difference between machine taps and hand taps is the material, because machine taps
