There are a number of significant differences between an end mill and a drill bit. The most obvious one is their function. A drill bit is designed to bore straight down into the material – metal, plastic, or wood – whereas an end mill is designed for sideways cutting. The two cannot be interchanged.
CNC Drill Bits
There is a wide range of drill bits available for CNC machines. The type of drill bit you choose will depend on the material you are working with and the project you are undertaking. Here is a rundown on some of the most popular drill bits.
Drill Bits for Metal Working
Indexable bit
This type of drill bit is designed with ceramic inserts and a hardened tip. This means it has cutting edges that serve the inner and outer spans of the cut and it need sharpening less often. An indexable bit can cut holes up to five times the diameter of the drill shaft.
Ejector bit
This bit is mainly used for drilling deep holes. The cutting edge is on the side and has the ability to make large radial holes. If you need holes with an even wider diameter you can use multiple bits.
Spade drill bit
This bit has a solid body and a removable metal bit that clamps into the body. It has a twist-shaped cutting surface with notches designed to prevent long chips that can potentially clog the drilling space.
Woodworking Drill Bits

Flat bit
This drill bit has a flat cutting edge and screw-like threads for drilling holes rapidly.
Augur bit
This bit also has a twist cutting edge, in this case it is wide with a single outer spur designed to cut the wood ahead of the bit’s edge.
Dowel bit
As well as a sharp center point, this bit also has cutting spurs to make holes faster. It can also be fitted with inserts to increase the cutting balance.
CNC End Mills
End mills are designed to cut horizontally and the shape you use will depend on the application. There are various types of end mills including:
- down-cut
- up-cut
- compression cut
End mills have varying numbers of flutes and shanks that very in diameter.
If you need some advice about using end mills and drill bits, contact us today. Our team at CAMaster has a vast knowledge base and we are committed to sharing our experience with you to help you take your enterprise to the next level. We can help you use machinery, hardware and software to facilitate and increase your company’s productivity and efficiency.