What are the differences between the AltMill and the LongMill?

The focus for the LongMill was to be a medium-format, hobby-focused CNC machine. Most users typically are looking to make things with a CNC in their spare time. Because of this, we made the LongMill the most affordable option possible in this size category, while being useful and effective enough to handle just about any CNC woodworking project you want to throw at it. We define LongMill’s success in its ability to make CNCing accessible to the average person.

The AltMill is designed to have the most “effective value” possible. Its success is defined by how much value it can create versus the cost of the machine itself. In simple terms, we wanted the machine that would bring the highest ROI and productivity. The AltMill focuses on the intersection where we believe the performance versus cost ratio is the highest it can be for these users.

Here are some spec comparisons to highlight the differences between AltMill and LongMill:

  • We’ve tested the AltMill to over 830IPM (although regular cutting speeds are in the 250 to 500IPM range) in cutting speed, while most projects we run on the LongMill run at 100IPM.
  • Based on our deflection testing, the AltMill is approximately 8x more rigid than the LongMill.
  • While the LongMill’s main bottleneck in cutting speed is in motor power and rigidity, the AltMill’s bottlenecks are in spindle power and the strength of the endmills. We estimate that the AltMill could handle upwards of 6KW of spindle power (although it’s not likely we’ll dive into that anytime soon because there are a lot more expensive electrical requirements we need to tackle to get this set up for the average user).

That being said, there is an overlap between these two machines. The process of using the AltMill is basically the same as the LongMill, which means that our resources and education translate over between the two machines, and the ease of use and process of using of both is similar. Additionally, both machines are designed primarily for woodworking use, and the types of projects we expect users to create will be similar as well.

Should I get the AltMill or the LongMill?

This depends primarily on your budget and what you want to do with the machine.

Here’s why you would want a LongMill:

  • You are budget-conscious. The total setup cost for the LongMill is roughly half the cost of an AltMill. Additionally, replacement parts and maintenance are cheaper overall.
  • You have limited power in your shop. We recommend having two breakers to power your LongMill and accessories such as the computer and dust collection, but in some cases, you can get away with one. On the other hand, you may need to connect the machine, dust collection, and spindle on separate breakers depending on power availability in your shop.

On the other hand, here’s why you would want an AltMill:

  • You need speed. The AltMill can cut significantly faster than the LongMill. We regularly run the AltMill over 5x the recommended milling speeds compared to the LongMill. The productivity of the AltMill is much higher.
  • You need more working area. The largest version of the LongMill has a working area of 48×30″, whereas the AltMill can cut 48×48″. This means you can process half of a standard 4×8′ sheet in one setup.
  • You need more precision. With ball screws and linear guides, the overall precision of the AltMill is better. In practice this may not matter as much with woodworking projects, you may see a bigger difference in the accuracy of parts for materials like aluminum.