If you work in the engineering tooling industry or are trying to source the right parts for a CNC tooling project, you’ll likely have come across the term ‘flute’. An integral part of any end mill or drill bit, and each are available with any number of flutes from a single one all the way to twelve. The most common drill bits and end mills come in either two or four flute, but less common variations include single-flute, and 3-, 5-, 7-, and 12-fluted bits.

What is a Flute?

A flute is a groove or valley cut out of the body of an end mill or drill bit. The flute allows for a cutting edge to be fashioned, and creates an area of empty space to allow the excavated material – known as ‘chips’ – to be ejected up the body.

How Does the Number of Flutes Affect Your Cut?

The number of flutes you opt for on your end mill or drill bit can have a serious impact on your project. There are some general principles you must understand in order to be able to properly assess how many flutes you require.

The more flutes a bit or mill has, the larger and stronger its core is. The core is the central point at which the flutes overlap, meaning that more flutes enlarges and reinforces the core. However, this also comes at the expense of a loss of chip ejection space, meaning the more flutes you have, the slower you are able to eject material up the bit. More flute also provides a much finer, smoother finish while fewer flute will leave a rougher touch.

How Many Flutes Do You Need?

Deciding how many you require comes down to adopting a balanced view of the feed rate vs the chip ejection. Some claim that adding more automatically gives you an equally higher feed speed due to the additional flute providing extra chip ejection space. However, as mentioned above, additional flutes also reduce the size of the chip ejection space that each has, so it won’t be as simple as a higher fluted tools means higher speeds!

Prima Tooling has over 40 years’ worth of experience and expertise in the tooling industry! For all your CNC tooling needs and incredible milling cutters like our carbide end mills, come have a chat with Prima’s expert team today.