Proxxon MF70 brushless belt er11 spindle upgrade

Upgrading a CNC MF70 mini mill spindle to ER11 chuck, steel spindle holder, brushless motor, 3 speeds belt driven for ranges between 0-7k high torque to 0-26k high rpm.

The brushless is a 3548 1100kv. The electronics is the esc for the brushless and a esc tester to control the speed, nothing custom made.

6 years so far going strong, bearings or the motor never failed. Machining aluminium is extremly easy with this setup and even steel with slow speeds.

[cnctopnet]

The aluminium plate, belt pulleys and the steel spindle holder are custom machined, this is not a commercial product or a kit. Please note the mill head was milled to fit the steel spindle assembly this makes the conversion not possible as a kit. This conversion is not something to be done without the proper tools, is not the parts only. One year later i can totally recommand if you can do it, its great, the bearings never failed again and the precision and power is insane, able to cut anything including steel. Night and day difference.

[joealexandersen]

This is absolutely brilliant. Definitely a long term goal of mine to do something similar!

[AveryKoff]

Greetings! Great conversion! I have a very similar motor bracket I had printed with glass-reinforced nylon and am in the process of motor selection, what model of motor did you choose? Your machine's longevity is what I find most impressive and is certainly worth emulating if possible; I'm currently looking at 3660 4100kv brushless RC servos but there's not much information on how well these motor types perform in this kind of role and I want to ensure I chose wisely. I've already purchased an ER11 spindle/bearing kit from Usovo in Germany (I did so prior to realizing I would likely need a more powerful spindle to mill aluminum) so I'm a little nervous if I can overcome the difference in shaft length via high rpm coupler, panel-mount bearing and shaft extension for the pulley. But choosing a motor has proven to be a real challenge. Thanks for sharing and any advice you might have.

[ali-ascentsayder]

nice work congratulations.I have a question, I will be glad if you answer.Can you give some information about the speed control circuit?speed control circuit diagram also how many kv brushless motor you use( 3674, 3670, 3650 why?)thanks

[mihaimastacaneanu]

Very good mod! Definitely I intend something like this! Can you please give some dimensions like steel spindle holder outer diameters - big/small; type/dimensions of ball bearings? Can the upper edge of aluminum housing be used for reference when drilling for steel insert; meaning is is square to spindle? How have you dealt with alignment when drilling?

[davideyt]

Have you CNCed the motor holder and belt pulleys ? or did you manually mill them? do you have any plans? or have you made the parts out of your head as you went? thanks

[baiden]

Hi, how did you measured the position of the hole for placing er-11 chunk on the aluminum plate
Because I can’t find a good method to measure it accurately

[mihaimastacaneanu]

Looking at your linked picture, it seems you were not that satisfied with the locking nut solution for fixing pulley, and changed it; is that right?

[juliaadams]

Hi. Would it be possible to post details of where you got the bits from? I am attempting to do something similar.

[EDUTAMARIU]

Now that is the way to do it!!!what power supply are you using? Thanks!

[leveckfamily]

I'm doing something similar, mind telling me how you removed the original spindle?

[dend]

Hi, how is the spindle fixed in the bearings? Is it a press fit or did mount something in the upper bearing?