A drilling machine and drill bits are one of the most fundamental hardware you can have in your home toolbox considering its applicability in just about any project. Be it a quick fix to your furniture, hanging an LED TV on your wall, or even a major room upgrade, those guhring drills in your house will get it done for you. But finding the right drill bit for your purpose can be quite a daunting task. Drill bits are available in a variety of shapes, sizes, and coating materials. It helps a great deal when you know your options. Here’s a quick overview of several types of drill bit materials and their design types brought to you by MK Industrial Suppliers - leaders in industrial tool supply & dealers in guhring tools.
Common Types of Drill Bit Materials
• Carbon Steel
Carbon steel bits are a bit inexpensive, but are not so firm on the hold and require frequent sharpening. They are mainly used only for drilling wood or a few soft metals. If they are overheated due to frictional heating while drilling, they may lose their temper, resulting in a soft cutting edge.
• High-speed steel
HSS bits are hard and much more resistant to heat as compared to high-carbon steel. They can be used to drill metal, hardwood, and most other materials at greater cutting speeds than carbon-steel bits.
• Cobalt (HSCO)
Cobalt 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. However, they are a bit more brittle than HSS.
• Carbide (Carb)
Carbide is the hardest but 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.
Types of Drill Bit Coatings
• Black Oxide is an inexpensive black coating which helps reduce friction and increase chip flow. It also provides heat resistance and lubricity along with protection against corrosion. It is not suitable for nonferrous materials.
• Titanium Nitride or TiN (gold color) is a very hard material used to coat a high-speed drill bit. It extends the drill life by at least 3 times. Even after sharpening, the coating provides an increased tool life.
• Titanium Aluminum Nitride or TiALN (violet color) is similar to TiN except that it increases life by 5 times or more. It is used in high-alloy carbon steels, nickel-based materials, and titanium and not used for aluminum.
• Titanium Carbon Nitride or TiCN (blue-gray color) is a coating superior to TiN. It is great for stainless steel, cast iron, and aluminum. It is harder and more wear-resistant than other coatings.
Design Features
• Common drill point angles
The most common angles for drills are 118° and 135°. These angles are existent from the time when drilling was largely a manual process, and the drill bits were conventional conical shapes. The drill points found on most jobber drills are 118°. They are typically used for cutting into soft metals such as aluminum. The 135° variant, which is flatter than 118°, is best suited for hardened materials, such as stainless steel.
• Flute Design
- Standard – This type is the most common with 30° angles
- Parabolic Design - The open structure of this design helps in the removal of the chip out of the hole. These are most effective in extra soft materials like plastics and aluminum.