Can the LongMill cut metals?

The short answer is yes. The LongMill, with proper settings and tooling, can make light cuts on metal. However, we generally do not recommend the LongMill for extensive metal cutting. The longer answer is provided below.

We’ve tested the LongMill on cutting softer metals such as brass and aluminum. CNC machines like the LongMill can take light cuts on these non-ferrous metals. Our team and customers have also tested cutting harder materials, such as steel, however, the LongMill is not effective with these materials. Most people will likely stick to aluminum as the metal of choice for cutting, which we will discuss here.

There are a few reasons why cutting aluminum on a hobby CNC machine compared to an industrial-level milling machine in general can be difficult:

  • Hobby CNCs are less rigid, and cutting on hard materials like metals is slower and more prone to chatter and imperfections.
  • The spindle or router speeds effective in cutting wood (around 10,000 to 30,000RPM), are much higher than what is typically used in industrial CNC machines designed for cutting metal. Running the speed too fast can result in faster tool wear and metal chips heating up and fusing to the bit.
  • Because the LongMill doesn’t have things built in such as flood or mist cooling, cutting needs to happen “dry” which also contributes to poor surface finish and faster tool wear.

If your goal is to primarily cut metals, we strongly suggest looking at a purpose-built metal milling machine.

However, here are some general recommendations that can help you cut aluminum.

  • Single flute bits, such as the ones in our Machinists End Mill Set, allow for bigger chips to be produced using hobby CNC hardware, which is ideal for milling aluminum
  • Use a spritz of lubricant to help cool your cut, such as WD-40 or isopropyl alcohol
  • Refer to our Feeds and Speeds resources for recommendations on tested settings for your machine