Thread Content
There are numerous tap grades available on the market today. Due to differences in the materials used, the prices of taps with the same specifications can vary greatly, leaving buyers confused about which one to choose. Here are a few simple methods to help you make a decision: When purchasing (except for taps without grooves, as no testing equipment is available), you can conduct a simple inspection (taking M6 as an example): 1. Check whether the thread chamfering at the front end of the tap’s groove is even, and whether there are any sharp edges on the cutting edge. A good tap will have a regular 7-shaped pattern, while a poor-quality tap will have an inverted 7-shaped or U-shaped pattern (this leads to two cuts when the tap is withdrawn, increasing the risk of breakage and affecting the accuracy of the thread)； 2. Check the heat treatment condition: Drop the drawing tap from a height of about 5 meters in a parabolic trajectory to see if it breaks; if it does, this indicates high brittleness ； 3. Break the tap and check its fracture surface: if it is obliquely elongated and the grains within the fracture (microstructure, 10.5#) are fine, this indicates that the heat treatment and material quality are good; if the fracture surface is flat or obliquely short, the grains (microstructure) are coarse, indicating poor quality. The quality of a tap depends on various factors, including its raw material, heat treatment, groove shape, precision, the equipment used, rotational speed, the hardness of the material being processed, as well as the skill level of the operator – there are many factors that play a role! When selecting a tap, special attention should be paid to its original material, heat treatment, and groove shape; for different types of holes that need to be drilled, it is recommended to use taps of different types! In practical operation, it is very important to sharpen the cutting edge, especially for stainless steel materials. Multiple cuts can be made, and the cutting tip should be shaped with a downward angle to enhance the strength of the tap. At the same time, proper cooling and lubrication are necessary (using a pump), and the tap can have a relatively long service life! In short, each situation is handled on its own merits.