Drill bits are tools used in creating cylindrical holes. Bits are held a drill which rotates the bits and provide an axial force which then creates a hole. There are also specialized bits dedicated for creating holes that are non-cylindrical.
Although drill bits can be made in any customized size a client may need, there are standard sizes of drill bits which manufacturers normally produce. Relevant standards’ organizations stipulate the sizes of drill bits that are conventionally manufactured and stocked.
There a several aspects to a drill bit’s geometry:
- The rate of twist in the drill, also known as the spiral, controls the rate of chip removal in a drill.
- The angle formed at the tip of the drill, also referred to as the point angle, which is influenced by the material the drill will be operating in. A larger point angle is used on harder materials while softer materials normally need a sharper angle. Having the correct point angle for the hardness of the material is very important because it controls the shape of the hole; wear rate, chatter, wandering and other characteristics of the drill.
- The lip angle determines the amount of support provided to the cutting edge. A bigger lip angle enables the drill to do a more aggressive cut under similar point pressure, compared to a drill that has a relatively smaller lip angle.
Some of the common types of drill bits used in metal, wood, plastic, and other materials are:
- Twist drill bits which have a cutting point at the cylindrical shaft’s tip
- Core drill bit which is used to enlarge an existing hole
- Center drill bits which are used to create an initial hole for a drill bit of a larger size
- Step drill bits which have the tip ground down to a different diameter
- Unibit, also known as step bit, which is a conical bit with a stair-step profile, and can be used for drilling a wide range of hole sizes
- Lip and spur drill bit which are used for drilling in wood
- Indexable drill bits which are mainly used in CNC machines and other equipments with high precision
A wide range of materials is used in making drill bits, depending on the required application. Some of the commonly used materials are: soft low carbon steel, high speed steel, cobalt steel alloys and tungsten carbide and other carbides.
SAN Tools supplies a wide range of threading tools, cutting tools, turning tools, lathe tools, carbide tools, boring tools, metal working tools, trepan and other customized tools. Our tools vernier caliper, CNC collets are used in cutting steel, cast iron and non ferrous materials in a wide range of industries including automobile, aerospace, earth moving, and heavy engineering and oil equipment, among others.