Spindle Options and fit

Hello everyone,

So I have my MPCNC operations and ready to go, but I need to pick a spindle. I was hoping to get a large 3 HP spindle with a VFD controller, but the bolt holes are 3.18 inch width and the MPCNC looks to be about 2.5" between the roller bearings that the spindle would mount to. I know I can design something to space it out a little and get it to fit. I wanted to ask if anyone else has mounted a larger spindle like this to their machine? How did you mount it? And if you had any problems with the heavier weight motor?

I’m looking to cut aluminum so I thought, what the hell, why not just get the biggest, badest spindle I can!

Hello Brian, welcome to the forum! Good job on setting up your MPCNC. If you want to mill aluminium, I don’t think the spindle is the main concern, I would think it’s the size of the build that would impact the cutting quality. (the bigger the less rigid) You’d be suprised how a 2HP machine (like the Dewalt or the Makita) can perform! If you are looking for some high-grade CNC that can churn through metals like butter, the MPCNC is the wrong lane. The MPCNC is super capable, you just have to adjust your mindset and expectations more carefully in terms of feedrate and DOC.

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I hear you. I’m not trying to build a Hass. Just want to cut a little aluminum and mostly wood and plastic. I bought a 3HP VFD spindle. I’ll try to update a post after I get it running for a while.

Thanks for the advice!

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3hp sounds huge to me, I’m cutting aluminium fine with a 500w unit.
I’d be careful with such a powerful spindle you’ll be able to destroy the rest of your machine in no time if it gets out of control.
I learnt this the hard way.

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I have a 65mm dia., water cooled spindle with a vfd. I printed a special mount for it. Works great but I had to add springs to the Z guides it so it didnt sink when Z was de-energized at the end of a cut. Works very well.

You have to watch the weight of the spindle with regard to acceleration, core, sagging etc.

I ordered a 80mm dia. spindle. Probably heavier than yours. Thanks for letting know about the weight. Sounds like I’ll probably need to adjust the z motor to hold it. Springs sound like a good solution! I’m committed now and will find a way to make it work. Thanks for the comment.

This is what i did on the Burly setup i have - also, be careful about the compression length. fully compressed the springs will have a lot of resistive force so you have to size the springs correctly.

9b7e2d14f11421ed6fe651aa7d585ce23a5319fa_2_502x500 58436821486b4f3cb62668a7651b3801d622fb55_2_690x500

What diameter spring? Looks about .90" thick x 1.50" spiral OD. Maybe 4 or 5" tall. Do you have any issue with springs moving around? Do you think making a seat like your cad model is necessary?