The tip angle of cemented carbide drills is usually called the apex angle. When cutting, no matter how much torque the machine tool is used, thecemented carbide drill  must still be able to withstand sufficient strength. If the torque of the machine tool is too large, the cemented carbide drill bit itself will not be able to bear it and twist off.

After one cutting edge of the top angle of the drill is determined, the other must be parallel, and the runout must be within 0.005. It is quite difficult to grind the standard drill point angle with ordinary machine tools. It's simple now. With the advent of a 6-axis CNC machine tool, the accuracy of the point angle of the drill bit can reach 1-2 seconds. Therefore, after a long time accumulation of experience, the best effect of cutting steel with a cemented carbide drill with an apex angle of 118°, so 118° becomes the standard drill apex angle.

So, is the tip angle of carbide drills all 118°? In fact, 118° is only a standard angle, which is most suitable for drilling steel.

However, if the workpiece material is changed during processing, it is recommended to change the size of the top angle of the drill. The drill point angle of hardened steel is 135-140 degrees, ordinary steel is 118-120 degrees, copper is 90-110 degrees, cast iron is 90-100 degrees, and wood plastics can be 60-90 degrees.

From the perspective of feed force, back force, etc., the cutting effect of 118° is very good, but in actual drilling, tool life must be considered. From this point of view, it is common to change the tip angle of the drill according to the material of the workpiece.

If you carefully observe the cemented carbide drill  bit, you can know that when the tip angle of the cemented carbide drill bit is 118°, the cutting edge is a straight line. However, at the production site, depending on the material, the tip angle of the drill bit may be greater than 118° or less than 118°. At this time, the cutting edge will become a curve, and the corresponding chip shape will be different.