What is drill bit geometry?
Twist drill bits come in various materials and diameters with different point angles designed to cut different sized holes in a variety of materials. And the harder the material, the flatter the point angle. Standard drill bits have a 118° point. A drill bit with a 135° point is designed for harder materials.
What is drill tip angle?
A drill bit has two cutting surfaces, one on each side of its center axis, that are cut at an angle of approximately 60 degrees.
How do you measure a drill angle?
The point angle is located on the head of the twist drill. The angle is measured between the two main cutting edges at the top. A point angle is necessary to center the twist drill in the material. The smaller the point angle, the easier the centering in the material.
What is a drill point?
It should come as no sur- prise. , then, that the drill point is where a majority of the tool’s cutting geometry is located. The drill point is crammed with a complex array of lands and edges, clearances and margins that all must work in unison in order to optimize a drilling operation.
Why drill bit angle is 118?
The two most common drill bit point angles are 118 degrees and 135 degrees. The difference between the two is the shape; a 118-degree bit is steeper, more pointed and has a smaller chisel. The 118-degree bit cuts more aggressively and is generally used for drilling into soft material like wood.
What is the best drill bit angle?
For hard materials such as steel and stainless, 135-degree bits are best. The shallow angle allows the bit to cut into the material without dulling quickly, however that same shallow angle makes for a bit that wants to walk around, requiring a center punch. The 135 angle is much flatter, as you can see here.
How do you tell if a drill bit is 118 or 135?
The two most common drill bit point angles are 118 degrees and 135 degrees. The difference between the two is the shape; a 118-degree bit is steeper, more pointed and has a smaller chisel.
What is lip angle?
Lip angle is the angle between the rake surface and flank surface when viewed on orthogonal plane. Point angle is the angle between the principal cutting edge and auxiliary cutting edge when viewed on reference plane. Lip angle and point angle are independent.
What is the hardest metal to drill?
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. Carbide (Carb) is the hardest and most brittle of the drill bit materials.
Why is it important to know drill point geometry?
Other aspects of drill point geometry will be covered that are rarely or ever covered in print since practically all drill point data deals with the same meaningless information telling craftsmen that “It’s important to Keep Drills Sharp.”
Which is drill point angle should I be using?
Racon® points: have a continuously varying point angle that generates less load and less heat while cutting into the metal and have a longer usage life. However, Racon points are not self-centering and must be used with a guide bushing.
What are the different types of drill points?
Other drill point configurations include: Notched points: were developed for drilling hard alloys and have reduced drag on the chisel edge. Helical points: have an S-contoured chisel that is self-centering and cuts close to actual drill diameter.
Which is the best split point on a twist drill?
Lip clearance angles of secondary cutting lips are generally the same as the primary lip clearance angles. Secondary point angles can be added on all twist drills for increased accuracy and durability. One of the most productive of all twist drills is the conventional split point.