When browsing drill bits, you'll notice they come in a variety of colors-white, black, tawny (amber), gold, and more. At first glance, these colors might seem like a reliable indicator of quality or performance. However, color alone does not guarantee quality. Manufacturers often use colors for marketing purposes or to mimic the appearance of high-quality drill bits, even when the underlying material or manufacturing process doesn't match. The true performance of a drill bit hinges on factors like material composition, manufacturing techniques, and quality control-not just its hue.
The colors of drill bits often correspond to specific materials, treatments, or production methods, offering some clues about their intended use. Below, we dive into the differences between drill bits of various colors, exploring what each typically signifies, how they're made, and their practical applications-along with caveats about judging them by appearance alone.
First of all, it is impossible to distinguish the quality of the drill bit simply from the colour. There is no direct inevitability between colour and quality. The processing process of different colours of drill bits is mainly different. Of course, a general judgement can be made from the colour, but at present, the poor-quality drill bit will also process its own colour to achieve the appearance of the appearance of the high quality drill bit.
What's the difference between drill bits of different colours?
High-quality fully grinding high-speed steel drill bits often appear in white. Of course, rolling drill bits can also be white by fine grinding the outer circle. The reason why it is high quality is that in addition to the material itself, the quality control during the grinding process is also quite strict, and there will be no burns on the surface of the tool.
Why They're Considered High Quality?
The grinding process requires strict quality control to prevent surface burns, which occur if the steel overheats and loses its temper (hardness). Fully ground HSS bits avoid this, making them reliable and effective.
However, rolled bits finished to look white can muddy the waters-color isn't a definitive sign of quality here.
Black is a nitride-treated drill bit. It is a chemical method to place the finished tool in a mixture of ammonia and water vapour. After thermal insulation treatment at 540~560C°, it improves the durability of the tool. At present, most of the black drill bits on the market are only black in colour (in order to cover up burns or black skin on the surface of the tool), but the actual use effect has not been effectively improved.Many black drill bits on the market are simply colored black (e.g., with dye or paint) to hide imperfections like burns or black skin from manufacturing. These don't undergo proper nitriding and offer no performance boost.
There are three processes for the production of drill bits, black for rolling, which is the worst. The white ones are clear and ground. Because unlike rolling, it does not produce high-temperature oxidation, the grain structure of steel is not damaged and is used to drill workpieces with slightly higher hardness. Tawny drill bits, known as cobalt-containing drills in the industry, are the unspoken rules of this drill bit industry.
Cobalt-containing drills were originally white and produced by grinding. When atomisation in the later stage, they were made tan (commonly known as amber), which is the best in circulation at present. M35 (Co 5%) is also gold. This kind of drill bit is called titanium plating drill, which is divided into decorative plating and industrial plating. Decorative plating has no effect at all. It's just good-looking and golden. Industrial plating is very good, and the hardness can reach HRC78, which is higher than that of cobalt-containing drills (HRC54).The tawny color is a useful hint, but unscrupulous manufacturers might mimic it-verify cobalt content through specs or trusted suppliers.
What Really Determines Quality?
While color can hint at a drill bit's type or treatment, it's not the whole story. The color of a drill bit offers a starting point to understand its potential makeup and purpose, but it's not a foolproof quality marker. Manufacturers can-and do-use color to deceive, making low-grade bits look premium. To get the best performance, dig into the specs: What's the material? How was it made? Is the coating legit? Pair that with a trusted brand, and you'll have a drill bit that performs as well as it looks-whatever its color.