500W spindle advice - *closed - went with Makita RT0701C instead*

So down the rabbithole I found a few things. The commercial product (with more complexity) of this:

Seems to be this: https://www.ebay.ca/itm/Frequency-to-Voltage-Voltage-to-Frequency-Voltage-To-PWM-Converter-Module/352560404838

Be aware there are two products that look almost identical, the above one operates on 0-1kHz, but does not have an optoisolator on the PWM input. The one that operates on 100+ Hz does have an optoisolator but will require setting the softpwm almost to maximum and then having limited (1 to 8) options for speed.

Brushless will do actual rpm control, although you may not be able to set a specific number. The controller will send more current if the motor is working harder (to a point). I don’t know how the cnc brushless motors handle it, but a RC brushless motor can suck so much current under loads that it will kill the controller.

PWM does work, pretty much. It’s always a diy endeavor though. If the 5V PWM can control it, that’s easy. 12V, sort of easy. The rest… :man_shrugging:

Most of the controllers are looking for a 0-10V analog input, it seems like. The ebay link above is for a pwm to 1-10V converter board. I guess I’ll have to give it a try. :slight_smile:

If you’ve been following my ramblings, it looks like those converter blocks will work with pwm frequencies as low as 100Hz but ideally would prefer 1k-3k range. Marlin on Ramps default is only 7Hz, so has to be scaled up via Soft PWM Scale:

// SOFT_PWM_SCALE to frequency:
// 0: 16000000/64/256/128 = 7.6294 Hz
// 1: / 64 = 15.2588 Hz
// 2: / 32 = 30.5176 Hz
// 3: / 16 = 61.0352 Hz
// 4: / 8 = 122.0703 Hz
// 5: / 4 = 244.1406 Hz

In configuration.h is the following: #define SOFT_PWM_SCALE 0 Setting it to 4 means only 8 possible settings. I think an adapter that allows lower pwm input is required.

I believe the main difference is that brushed motor will be speed driven in theory, the motor RPM being directly dependant of the position of your potentiometer, while brushless motors will be torque driven, increasing the torque to get to the deisred speed. That translates into a more stable speed under load.
And also, less noise.

Just take the biggest, leaves you more possibilities

Never done that and I don’t really see the point in doing so. Is there any real advantage over just manually turning the potentiometer? I thinks it’s just easier to use the pot and it gives you the opportunity to adjust much faster during the cut in case of any problem.

I’d just say that these motors aren’t really good from my experience and several people already pointed out some issues with them, mainly too much chatter while cutting, not enough power and not enough rpm. If you can, you’d better go for a simple Dewalt DW60, they’ve already proven to be good in all situations

This is backward. The brushless controllers have to know the speed because they need to know when to switch the current direction. Brushed motors just dump more or less current to adjust torque.

I have a zip router already but it’s way too loud to use for long cuts. I don’t have a separated building or shop, my mpcnc in inside the house. I’m fine with slowing down the cuts if it’s not 130dB.

Well, after some extensive research and anecdotal advice I think I’m going to go with the Makita RT0701C. Seems well liked for the purpose, not too heavy but powerful enough, and not overly expensive or complicated to control. I’m adding an ER11 spindle extension for smaller bits as the makita seems to lack smaller collets for some reason. O_o Anyway, this is the ER11 extension and bit set I went with, if anyone has the same issue. https://www.aliexpress.com/item/32871091240.html

That’s not what I mean, its a bit difficult to explain, and unfortunately I don’t really know how to describe what I’m talking about. This has to do with the way the controller sets a defined speed and correlates the potentiometer position when you twist it. It can either be torque or speed mode. If it is torque driven it still has to know the rotors position and speed, but it will give you a constant torque for a set potentiometer position. Anyway, it’s not really important and I’m not even sure this applies to those cheap sensorless controllers so you can just forget what I said :wink:
These controller behaviours are what separates garbage controllers from the good ones on electric vehicles, and from what I know the torque control strategy cannot be applied to brushed motors. I think it’s also named torque vectoring.

Most of the noise will come during the cut, so even if the spindle itself is quiet, the bit rubbing against the material will remain the source of most of the noise. I suggest you to build some kind of enclosure, it will also have some other benefits, like dust protection.

Yeah that seems to be a nice solution, many people said that this router is pretty good :slight_smile:

Well, my old zip router was so loud I couldn’t hear a difference between when it was cutting and when it was just turned on, so it’s already better. :wink:

What hole diameter did you get? I don’t understand what the different options are for.

A is hex, M requires a special tool that fits into the grooves. L is length in mm. The one I linked here is 6mm not 1/4" shaft so you’ll either need to find a 1/4" shaft one if your router is Imperial, or get a 6mm collet. I ordered one from the UK.

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I’m soo confused by router options! This item ships with shaft, collets and clamping nut. My router is European, so I expect it to be metric. Do I need anything else than this, to use 1/8"/3mm end mills? I assume there’s no reason to go for anything else than the hex option? I’m sorry for my lack of brain power!

Nope, you’re good. Here is the list of supported bits: 3mm,4mm,5mm,6mm,7mm,1/4,1/8

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AAahh, I’m soo slow! It seems that this extension rod goes into the existing shaft, so the total length endmill shaft would be much longer? I tried to figure out if I could dissasemble the router, and pull out the original shaft, to insert the ER11 rod. It seemed impossible.

If this extension extends the lengt of the router mill - wouldn’t a simple 1/8" collet do better? (Granted I would only need 6mm and 1/8" bits) For example this one: https://www.amazon.com/Makita-763626-6-Collet-Cone-8-Inch/dp/B00018ABSW or the one from Elaire Makita Router collet adapter

Wouldn’t these options provide a better stability and less length to the mill shaft? I don’t know your precise needs, I’m thinking of my own setup here.

Yes, those are good points. For me, I actually wanted to extend the shaft somewhat so it’s easier to use 1/8" bits, which tend to be much shorter than 1/4" ones. I’m going to cut it so the ER11 collet is tight to the bottom of the router collet.

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The problem with those collet extensions is they add quite a bit of lever action to the z assembly. I think that was a big contribution to Tom’s horrible cutting in his build video.

Even if they are shortened so they are touching the chuck? If it was possible I’d just replace the Makita collet with the ER11. There’s no good reason for there to be so many different standards for collets, and Makita doesn’t even make a 3mm or 1/8" collet, you have to get them 3rd party.

Yea, it’s still adding length. We want as little stick out from the z assembly as possible. I have 3rd party collets for my dewalts, they’re worth it. Most of the time, they’re better made than from the oem.