Pwncnc spindle insight

In addition to what @Aiph5u says, a plus for water cooling in my head is when milling aluminum. While i can put a filter on an air cooled spindle (I use a repurposed sock on my Makita) to keep aluminum chips out, I intend to go water cooled when I upgrade so there is no place for conductive chips get in the spindle.

I am considering the 1.5kw, 110v, er20 version from pwncnc. While upgrading to 220v is easy in my tiny shop, I’ll likely move in a couple years and don’t want to worry about trying to install 220 in a new place before I could get up and running. I have not found that particular combination, 1.5kw w er20, elsewhere. If I go the roll my own from parts route, I’d go 2.2kw 220v. Don’t really need the extra power but would love to have er20.

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I think you might find this post from @Echd and @Aiph5u of value.

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Additionally, per @Aiph5u you can use a 2.2kw 110 spindle with 1.5kw settings and get an er20 collet more cheaply that way. I agree that the extra power is very likely unnecessary for wood and probably anything metal you may do on a onefinity.


Wish I’d understood that 6 months ago :joy:

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OMG I feel just a touch slow @Echd. :joy:

Thank you for pointing that out. In spite of knowing a more powerful vfd could work for a less powerful spindle (future proofing with a good vfd buy and cheap spindle) by stepping down setting, it never occurred to me to go the other way around. Brilliant.

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Can’t tell you how much I appreciate all this feed back from you and others. Your point on the Collet is a good one, I will need to pay attention to that. I have lots of 230V outputs as it is the standard for most of the heavy machinery I use. I even had to install a three phase generator (unit with idler motor) for a couple of large machines I have. As a rule I prefer to swap voltage for amps and reduce losses in the wiring even though I recognise that I won’t be running out of amperage head room on 120V. I notice that you put “presumably” in the comment about the 220V spindle being of higher quality. I would be interested to know if others have found this the case as it would be my guess as well. From a reliability point of view I would go with the 220V in either case as it would run cooler windings and heat is the main killer of winding insulation in motors. You definitely got a screaming deal on your spindle and even if you upgrade its a good backup. I will definitely run the Modbus as you mentioned. I just like the integration of it (I am a bit of a nerd at heart). My experience with EMI in communications links is that people often make the mistake of grounding both ends of the shielding which renders it useless and creates ground loops rather than draining off the noise. I definitely want to have my equipment grounded though as any good automation person will tell you a huge percentage of the problems in automation are caused by floating grounds (maybe not relevant here but just a best practice thing). Also I believe that you can forgo the magnet line from your probe when you have an equipment ground and perhaps avoid the mistake of forgetting to remove it before starting. Thanks again for all your guidance, very helpful. Cheers John

That is an excellent synopsis of how the VFD functions and why someone might want to start with a 220V system. Thanks for the link!

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Great discussion, as I am about to order an 80mm spindle as this will be my introduction to CNC. I hope to avoid not having to upgrade too quickly after my initial setup.

220 is not feasible without some major core drilling to run power, current 110Vac supply is 15 amp rated so the 2.2 KW 110 spindle amps would exceed wiring.

This leaves me at 1.5 kw 110 80 mm spindle.

My only decision I’m trying to decide is, air or water cooled?

Cool down being one pro for water cooled from what I’ve read in this thread. I just wonder about leakage, or any cons for water cooled besides cool down and no pathway for debris through the fan.

Any advise from those with experience is greatly appreciated.

Hey John,

I don’t know if you plan to buy the Onefinity Standard Series with the Buildbotics-derived Onefinity CNC Controller or the Onefinity Elite Series with the MASSO G3 Touch CNC Controller, but the latter does not support Modbus. On the Masso, the RS-485 hardware is present, but its support is not yet implemented.

But all VFDs I know support spindle speed control by analog voltage, like shown here:

In the diagram above, it’s a potentiometer that controls the analog voltage – an external spindle speed knob. With the Masso CNC Controller, instead of connecting a potentiometer, the analog voltage input of the VFD is connected to pin 1 of the spindle connector of the MASSO G3 as shown here.

The spindle speed control with an analog voltage is not as exact as sending a digital RPM value over ModBus, and analog voltage control has to be calibrated, but many people use it successfully.

I don’t know if you belong to the disciples of that religion (there seems to exist such a one on the web and social media, the Ground Loop Exorcists of the Holy One-sided Grounding), but if you plan to connect a spindle to a VFD yourself, I believe you should first have read this:

You could also simply look into a good VFD manual:

– Source: Omron MX2 User’s Manual

You can find that in every serious VFD manual, but in “Begin with the End in Mind - Proper VFD Cable Termination”, it’s explained why.

There exist situations where it is necessary to ground only one end of the shield of a shielded cable, that are situations where a ground loop could appear. But this is definitely not the case on a shielded power cable between an induction motor and its VFD.

And regarding the RS-485 serial line for the Modbus communication (a balanced line by the way), I would ground both ends too, as the setup is connected on the same local installation and the same ground:

– Source: Omron MX2 User’s Manual

An example for a ground loop is if your cable TV provider grounds their cable in their distributor board out there a few miles down the road and then it is grounded again in your house at your cable TV wall outlet or in the receiver. This can produce a lot of hum that deteriorates the signal. This is because in an unbalanced line, ground participates in signal flow (=ground is a circuit conductor that completes the circuit back to the source here). The solution here would be galvanic isolation. I have an isolation transformer as a sheath current filter in front of my cable receiver, and I have much better signal quality since then.

Note that what is more important than the shield on balanced serial lines, is the proper termination:

Then you might be interested in:

I think my post which answered the question “Which is better, 110 V or 220 V?” was this one.

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One other point I did read ( keeping in mind I don’t have first hand experience) is that the air cooled version exhausts in such a way that it kicks up a lot of saw dust and with product like MDF that might be annoying. Perhaps others with first hand experience can weigh in on this aspect.

Hey Bill,

this is discussed from time to time in the forum, e.g. here or cheap chinese 65 mm spindles with hairline cracks

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Hey John,

only if there IS dust. I would always take care that the dust is collected entirely at its source, i.e. the milling bit.

Air-cooled spindles suck their air at the connector (upper) end and blow the air out at the shaft (lower) end.

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I am leaning towards the PwnCNC version. Not sure the origin of supply. I’ll read on some more. Thanks for directing me to the thread

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Thanks so much Aiph5u. You have once again given me a ton of very useful info. I am planning on getting the Elite. However I was not aware of the issues with trying to communicate with all the different manufacturers VFDs and therefore the lack of support for Modbus. I am curious to understand how the Buildbotics communicates with the VFDs, probably a bit out of my depth but I would have to assume that it is another protocol? It would be nice if 1F would tackle this issue by offering a couple of “in house” option for the VFDs and spindles and have Masso write some code accordingly, but perhaps this is naive thinking on my part. I will monitor the Masso link that you sent to see if there is any progress. Bottom line is that I will go with the Elite series either way. I also see that my experience with high speed communication cables is not applicable in the power domain and probably more of a liability. :sweat_smile: On the dust issue the youtube video I saw on this indicated that despite the suction around the milling bit that the excess air from the cooling focused at the same point caused some of the sawdust to become airborne and escape. It seemed to make sense but I have NO first hand knowledge on this and it’s a moot point for me anyway as I will do the water cooled for the reasons you mentioned.

Hey Bill,

the VFD that Daniel @PwnCNC offers is a DELIXI CDI-EM61. Regarding the spindle I’m not sure but in this thread there is G-Penny mentioned.

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Hey John,

OnefinityCNC frequently stated they will never support VFDs/spindles

Onefinity recommends the Makita hand trim router but I can’t recommend it since it is not allowed for use in a stationary machine (is a warning in the manual and it is confirmed that you loose warranty in the same moment you mount it into a CNC) and it is likely to burn your workshop down.

Unfortunately there is still no 43 mm mount available for the Onefinity so you don’t have the chance to use a professional, CNC-approved milling motor like AMB (former Kress), Suhner, Mafell which are plug-and-play and require no VFD. So the only alternative to the Makita hand trim router on the Onefinity is a spindle with VFD. If you manage to install one, it is the superior motor, induction motors are the workhorse of the industry and their efficiency is excellent, and you have a constant torque from 6,000 to 24,000 rpm (while with the Makita trim router, when you have torque, you have no speed, and when you have speed, you have no torque). High torque at high speed is what you need when milling wood.


Just to add in on the magnet and touch probe. The vast majority of chinese spindles for some reason have their ground pin connectors in the spindle completely absent. I have no idea why. I feel confident that the pwncnc ones do not have that issue.

However, fear not; as it is very easily rectified. Remove the top “lid” from the spindle motor and just solder a short length of wire from the ground to the location inside of the spindle body.

Upon doing so, the touch probe will work as described. Please bear in mind many of them are wired “backwards”, and you will need to replace the wire leading to the touch probe with the one leading to the magnet. You will know this is case if you attach the magnet to the spindle and it triggers the detection immediately. Very simple to fix so do not let it deter you… the connector is a simple banana plug jack like any speaker may use.


Building on some of our earlier discussions, I would like to add that I received my 2.2kw spindle today. While the 1.5 I have works fine and is not in any way deficient, the overall quality is higher. Both came from the Huanyang Store on Amazon so im relatively assured that both are legitimate (as there are faked huanyangs)

Also, it came with a ground wire actually attached.

Doubt I’ll ever see any real difference in use, but i am itching to try some of these monstrous 1/2" vbits… lol (4 flute “speed tiger” chamfer bits compared to the Cadence Mfg “GrooVee Jenny” bits)


I’m looking at the PWN CNC 80mm spindle. I am leaning toward the air cooled 1.5 due simply not wanting to mess with coolant lines and wanting the ease of using a 110v outlet. Is anyone running the 80mm 1.5 air cooled setup? If so, how do you like it. Is there a significant difference in performance between the 1.5 and 2.2, or the air cooled vs. water cooled? Thanks in advance.

Hey Rick,

if you want to run a 2.2 kW spindle on 120 V, the needed rated input current of the VFD will be higher than any domestic circuit in the U.S. is able to provide. That is the reason why Omron/Hitachi produce VFDs for 120 V only for spindles up to 0.75 kW, and why cheap chinese VFD “manufacturers” simply omit the rated input on their VFD nameplates and manuals (see here). That’s also why Daniel of PwnCNC says he does not offer a kit for 2.2 kW @ 120 V. They offer only 1.5 kW @ 120 V, or 2.2 kW @ 240 V.

Air-cooled are often required to run at least at 8000 rpm, while water-cooled can run as low as 6000 rpm.

Water-cooling also means that the spindle can be cooled after it is stopped, until it is really cooled down.

Welcome to the forum!

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