Why are there color distinctions for drill bits? Many people don’t know the reason for the distinction.

Drilling is a very extensive processing method in the manufacturing industry. I believe that the friends who are often on the front line of drilling will not be unfamiliar with the understanding of drill bits. When purchasing drill bits, drill bits will have different materials and different colors. What is the difference between the drill bit? Does the color have anything to do with the quality of the drill bit? Which color drill bit is better to buy?

Does the color of the drill have anything to do with the quality?

First of all: it is impossible to distinguish the quality of the drill from the color alone. There is no direct and inevitable relationship between color and quality. Different colors of drills mainly have different processing techniques. Of course, a rough judgment can be made from the color, but the current poor quality drills are also It will process its own color to achieve the appearance of a high-quality drill.

What is the difference between different colored drill bits

High-quality fully ground high-speed steel drill bits often appear in white. Of course, rolled drill bits can also achieve white color by fine grinding the outer circle. The reason for high quality is not only the material itself, but also the quality control during the grinding process. Quite strict, no burns will appear on the surface of the tool. Black is a nitrided drill bit, which is a chemical method to improve the durability of the tool after placing the finished tool in a mixture of ammonia and water vapor, and after heat preservation at 540-560C°. At present, most of the black drill bits on the market are only black in color (in order to cover up the burn or black skin on the surface of the tool), but the actual use effect has not been effectively improved.

There are 3 processes for producing drill bits, black is rolling, the worst. The white ones are edged and polished. Unlike rolling, high temperature oxidation does not occur, so the grain structure of steel is not damaged, and it is used to drill workpieces with slightly higher hardness. The yellow-brown drill bit is called cobalt-bearing drill in the industry. This is the unspoken rule of this drill bit industry. Cobalt-containing diamonds are originally white, and are produced by grinding. When atomized later, they are made into yellowish brown (generally called amber), which is the best in circulation at present. M35 (Co 5%) also has a golden color. This drill is called titanium-plated drill, which is divided into decorative plating and industrial plating. Decorative plating has no effect at all, it is beautiful and golden. Industrial plating is very good, the hardness can reach HRC78, which is higher than the hardness of cobalt-containing diamonds (HRC54°).

Since color is not a criterion for judging the quality of a drill, how exactly do you buy a drill?

Judging from experience, generally speaking, the white ones are generally all ground high-speed steel bits, and the quality should be the best. The gold ones are titanium nitride plated and are generally either the best or the worst fools. The quality of black is also uneven, and some are made of poor carbon tool steel, which is easy to anneal and easy to rust, so it needs to be blackened.

Generally, when buying a drill, you can see the trademark on the drill shank and the logo of the diameter tolerance. The logo is clear, and the quality of laser or electrical corrosion will not be too bad. If it is a word-molded word, if the edge of the word is bulged, the quality of the drill bit is poor, because the bulging outline of the word will cause the clamping accuracy of the drill to fail to meet the requirements, and the edge of the word is clear, which is very good and the cylindrical surface of the drill shank The junction is of good quality. In addition, it depends on the cutting edge of the drill tip. The edge of the fully ground drill is very good, and the helical surface meets the requirements, while the quality of the poor quality is very poor at the rear corner surface.