What You Need to Know About Cylindrical Bits for CNC Machining Centers

The final result is the same, a cylindrical hole. But cylindrical drill bits for CNC machining centers are quite different from those you use on a normal drill to drill metal. With these high-speed cutting tools, you can achieve specific results based on a clear need: maximum possible precision on large operational quantities. When you use a tool like this, you're looking for resistance to very high rotation speeds and constant feed forces, but also masterful execution.

CNC (Computer Numerical Control) machines are automated machines capable of performing multiple operations - milling, turning, tapping, reaming - with maximum precision. And without the operator having to move the part from one machine to another. And when you need a cylindrical bit for drilling, do you only have to choose tools with specific characteristics?

What are Cylindrical Drill Bits for CNC Machining Centers?

The first step of this guide is dedicated to definition: cylindrical drill bits for computer numerical control machines are axial cutting tools equipped with very high precision. The purpose is to create holes that meet specific requirements: this is achieved thanks to bits made mainly of hard metal or cobalt super-rapid steel (HSS-Co).

Cylindrical drill bits for CNC machining centers have a smooth cylindrical shank or with Weldon drag plane, which guarantees perfect centering in high-clamping chucks or hydraulic chucks. On these bits we have optimized cutting geometries, with self-centering sharpening and internal lubrication holes that allow to sustain high cutting parameters, guaranteeing tight dimensional tolerances and a surface finish that reduces or eliminates the need for subsequent reaming operations.

What are the Technical Features of These Bits?

We have already listed some aspects. But for completeness of the guide dedicated to cylindrical bits for CNC machining centers, we must dedicate space to technical aspects, composition, shape, and materials of these tools based on precision.

Let's start with the metal used for the bit: in the CNC universe, materials are used that can maintain the cutting edge even when the bits or mills become red-hot. So cylindrical bits are often made from hard metal Widia (HM/VHM), a tungsten carbide powder synthesized with cobalt with a breaking strength of 2200 MPa and a hardness of 91.9 HVA.

With these solutions, cylindrical and precise holes are produced. Alternative option: for these bits, cobalt super-rapid steel is also used: tougher and less brittle than hard metal, it is used when the machine is not perfectly stable or for specific materials.

Modern bits for CNC machines are also self-centering and have a sharpening that prevents slipping on the workpiece surface at the beginning of the hole. The shank (the cylindrical part that is clamped in the chuck) is ground with extreme precision.

Precisely because it must offer a secure grip and absolute stability. The mechanism ensures that the bit rotates perfectly in axis, with minimal run-out: if it even flutters slightly, its lifespan drops drastically. And the precision suffers from it.

What are the Main Uses of These Cylindrical Bits?

These helical bits for CNC are not generic tools, they are used in modern industrial production. Their main use is high-speed drilling, but applications vary depending on the sector. For example, these tools are used to create passages for coolant and oil in engine blocks, cylinder heads, and transmission components of an engine.

CNC bits are also used to drill structural components in aerospace aluminum, titanium, or special alloys used for medical components. In summary, where maximum attention is paid to dimensions and tolerances, cylindrical bits are used.

Remember that these cylindrical hard metal bits for CNC - designed for simple drilling cycles G81 or with procedures to unload the chip like G83 - can be sharpened and recoated. If poor work is done in regeneration, the bit loses its characteristics, but there are specialized centers that use CNC machines to restore the bit's geometry.