MPCNC with 3kw Spindle?


I’m going to start to build my MPCNC and would like to know if it’s possible to add a 3kw spindle to it? Will it handle it?

I’m going to CNC mostly aluminum (6070 or 6082) and carbon fiber parts with 5mm thickness, I’ll need the stronger spindle possible.


It all comes down to weight. How much does the spindle weigh? We’ve done aluminum and carbon fiber with the dewalt routers, and the little 300 watt dc spindles.

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Carbon Fiber is as easy to mill as plastic, except it dulls bits extremely fast and should be milled wet as to not breathe the dust. The Dewalt (600W) has plenty of power for aluminum but if you wanted to go stronger 800W would be more appropriate, 3000W is overboard and so big you will actually decrease the rigidity of the machine by increasing the Z axis lever arm as Barry pointed out the added weight will decrease how nimble the machine can be a negate any speed gains a larger spindle could in theory give you. More in the FAQ’s.

CNC’s are a balanced system, larger steppers or spindle don’t change the rest of it so there is typically no gain, just a negative effect on any well balanced system.

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A 3kw spindle should weigh about 7.8kg. Do you think the MPCNC will be able to handle it?

17 pounds, no, it’s not going to handle that weight very well at all. My spindle is like a pound. The DeWalt 611 and 660 is around 3 pounds.

Weight is the least of the issues with something that powerful. The startup torque would probably rip the feet off the table.

That is 100% not an option for smaller CNC’s. Don’t waste your time.

Holy crap. Imagine a startup of a motor that size ripping the machine off whatever you screwed it to. The immense power of such a spindle…it is so tempting but totally unneccessary!


My dw660 never bogs down no matter how I try. My machine deflects hard before I hear the rpm slow down a significant amount.

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Alright, so it’s a big no-no for a 3kw spindle. However, a 2.2kw spindle should work, right?

I just saw a video of a guy uses a 2.2kw with his MPCNC. Anything special need to be done in order to make it to work?

If you want to use a spindle, just build a normal gantry cnc, way more rigid, with bigger steppers. You’re trying to shoehorn a HEMI into a civic. The MPCNC wasn’t designed to use one of those kinds of spindles, it was designed to use a handheld trim router. Just like the HEMI in a civic, you’ll never use half the power available to that spindle. At least build it as designed, then modify it if you think it’s not going to work the way you need it to.

Biggest I can recommend is 800W. I have no idea what you think a giant spindle is going to get you. That isn’t how any machine works.

Think of it this way, what if you replaced each of the steppers with 5HP lawnmower engine. Just because they are strong gets you nothing, they are also heavier meaning the accelerations would have to be extremely slow and you have no control of them. Machines are balanced at every decision to. The frame fits the steppers fits the power the spindle has. What if a dentist came at your teeth with a Dewalt cordless drill, it has 100x’s the power of his dental drill but do you think he would have the dexterity to use it, or is it too big and heavy to be wielded properly?

This has come up many times before and is in the FAQ’s.

Now, that I’ve got to see. I visualize the 5HP lawnmower stepper version using 6" conduit and concrete blocks drilled to hold them on the corners… Dang that guy is going to be loud!