The drill bits are special cutters that are used to drill through holes or blind holes in solid materials, and also reaming holes in existing holes. The most commonly used drills are twist drill, flat drill, centre drill, deep-hole drill and trepanning drill. Although reaming drill and M drill can’t be drilled holes in solid material, but they are also customary to put them in the drill bit classes.
The drill bits are mainly made of high speed steel, powder metallurgy and cemented carbide.
Classification by material of drill bits:
1. High-Speed Steel (HSS) Drill Bit
High-Speed Steel (HSS) is a popular material good for drilling into soft steels as well as wood and plastic. IT’s an economical solution for most maintenance drilling applications.
- Basic on HSE feartures heat and wear resistance.
- Special shapes of helical flutes combined with ‘X’ thing provide low thrust force and excellent chip removal.
- Suitable for drilline General Stells, Stainless Steel, Aluminum Alloy and Cast Iron, etc.
Hollow drill bit of high-speed steel material is also known as core drill bit or tapper.
Cutting depth: 35MM, 50MM, 100M;
Suitable drilling machines are: magnetic drill press, magnetic drill, suction drill, annular cutter, machine tool, bench drill, boring anchor, etc.
High Speed Steel Stub Screw Machine Drill Bit
- Made of 8 percent cobalt and high speed steel
- Suitable for drilling in thin materials with portable drills
- ANSI Specifications met
Screw machine drill with gold flutes. Drills suitable for drilling in thin materials with portable drills. Special twist drills for automatic and turret lathes. ANSI Specifications met.
2. Cobalt (HSCO) Drill Bit
Cobalt (HSCO) is considered an upgrade from HSS because it includes 5-8% Cobalt blended into the base material. This is a great option for drilling into harder steel as well as stainless steel grades.
The cobalt drill is divided into two materials: M35 and M42, they have a good bending strength and high hardness, usually between hrc65-69, most of the drills used to drill stainless steel that are such drills.
3. Powder HHS Drill Bit
Powder HHS has a good grinding performance, heat treatment stability, toughness, good red hardness and wears resistance. It is also suitable for drills with higher strength machining requirements.
4. Cemented Carbide Drill Bit
Carbide (Carb) is the hardest and most brittle of the drill bit materials. It’s used mostly for production drilling where a high-quality tool holder and equipment is used. It should not be used in hand drills or even drill presses. These drill bits are designed for the most demanding and hardest materials.
The surfaces of high quality cemented carbide drill bits are coated with coating treatment, such as AlCrN, its coating is single-layer, thickness of 4μm, micro-hardness of 3200HV, friction coefficient of 0.35, and the thermal stability comes up to 1100℃.