How to distinguish quality drills by eye in a store? The old master showed how to choose HSS drills and the most top-end

Repairs often require the use of a hammer drill, drill or screwdriver. You can't do without such tools. You can drill any hole in the wall, tiles and other materials.

A quality tool is half the battle. I also need to buy high-quality consumables (drills, drill).

Drills are different for different jobs and materials. There are drills for wood, concrete, metal. One old turner taught me how to choose drills, I share with you.

How to choose a quality drill bit in the store?

Pay attention to weight. High quality will weigh a little more. For example, a cheap drill weighs 12 grams, and a better quality one already weighs 15 grams. You need to choose drills in the store like this. Pick up one drill, hold it in your hand, estimate the weight and compare with the other. Experts advise buying drills that weigh from 14 grams.

Workmanship. It is necessary to buy drills that are made by milling with further grinding. The cutting parts of the drill are ground. Designation HSS-G.

Hardness. If you take a glass and run a drill over it, then a poor quality will not leave any special marks. And if you take a high-quality one and try to scratch glass with it (for example, a glass bottle), then the difference will be visible immediately. The drill leaves a visible mark.

Sharpening angle. Noteworthy are those drills that are sharpened at an angle of 130-135 gr. (for steel and bronze). If you need to work with softer material, then the sharpening angle is 100 gr. For cast iron, brass 110-120 gr.

Fine work requires precision. All drills are classified into 3 accuracy classes. The increased accuracy is marked with A1. Medium, normal - B or B1.

There are drills with a special coating. They reduce heat during operation. It has the designation HSS-TiN (titanium nitride coating, sputtering). You can drill cast iron, steel. The drills are golden in color. Minus: sharpening is not recommended. If used up, throw it away and buy a new one.

HSS-TiAlN coated drills are even more wear resistant. They have 3 coatings (titanium, nitride, aluminum). But I have not found such in the store. These drills retain their characteristics even at high temperatures of 700 g.

HSS drills differ in additives during manufacture. 3 varieties: tungsten (T1-T15), molybdenum (M1-M36) and alloyed (M41-M62). Tungsten HSS drills are considered to be the best.

Top-end - cobalt drills

This is the same high-speed steel HSS, only with the addition of cobalt (from 5%). The color of this rig is slightly brown. HSS-E and HSS-Co marking. Core drills can be 8% cobalt. Such equipment can withstand the highest temperatures, less bluntness and less wear.