This article will explain the 7 main basic features of a twist drill: Point angle, cutting edge, Chisel edge, flute profile, Web thickness, Edge line, and helix angle, will explain how they affect in an application.
As you know, different material place different demands on the tool. So how to select of the twist drill, let’s begin from the below points.
- Point angle
The point angle is located in the head of the twist drill, which is measured between the two main cutting edges at the top. To center the twist drill in the material is the function of the point angle.
How many different angles we have? Heygo Drills mainly have 118° and 135 two different angles. Smaller point angle will have easier centering when processing, also is not easy slipping on Non-vertical working material. Bigger point angle, the time of drill is shorter but will face bigger pressure and hard centering.
Generally, 118 suitable for general steel, 135 degrees is for hard-cutting material.
- Cutting edge
The main cutting edge is responsible for the drilling. Longer cutting edge has higher cutting performance than the shorter one. But sometimes, the difference is small.
- Chisel edge
The cut chisel edge is in the middle of the drill tip, drilling into the material by extrusion, which will cause heat increased and power consumption. The length of cut chisel edge decides the drill’s sharpness. Short cut chisel, better centering, high sharpness. But these features could be effective by the web thickness.
- Flute profile
The flute is for chips removal. Wider flute, better chips removal performance.
No good chips removal means higher heat generation. This will cause the drill to anneal and breakage the drill. Wider profile, flatter flute; Thinner profile, deeper flute. The depth of the flute decides the thickness of the web.
- Web thickness
The web thickness is the determining measure for the stability of the twist drill.
Twist drills with thick web have higher stability and suitable for higher torques and harder materials.
In order to better centering, Heygo Tools will grind the two back angle.
- Edge width
The width of the edge line affects the sharpness and surface finish of the holes. Wider edge line has higher stability, not easy breaking, suitable for not good work environment or the material with higher content of impurity. Narrow edge line, the strength is low but higher sharpness, suitable for good drilling equipment and high surface finish working material.
- Helix angle
The basic feature of the twist drill is the helix angle. The larger angle is suitable for soft material with a long chip, the smaller angle is suitable for hard cutting material with a short chip.
The running angle is 23-38. According to the market’s different material, we develop two kinds straight shank twist drill: One for general steel with 23-30 degree, the other one is for stainless steel with 35-38 degree.
With the above information, you may have an idea of how to choose the drill bit suitable for you. If you have any questions, please do not hesitate to contact us. The response will be within 2 hours in day-working time.