Pwncnc spindle insight

I’m looking in to purchasing a Pwn spindle (1.5kw 110v air cooled) I would like to know some insight from people that have it as far as durability and would you do it again or go another route.


I debated the same for a while.

Per the owner they are chinese spindles made by GPenny, i guess to his specifications. I would ASSume the VFDs also come from the same manufacturer.

I do this for a hobby, not a business. At first glance there seems to be a lot of black magic around spindles and everyone speaks of them in hushed tones and acts as if they’re very complex. In reality, I bought an amazon return huanyang spindle and vfd for $150 and the extent of setup was finding some shielded 4 connector wire, soldering some connectors to the aircraft connector, adding a ground wire to the inside of the spindle motor, soldering some spade terminals on the other end, and following the very easy programming instructions on the Buildbiotics website. Oh, and attaching a scavenged power cable to the VFD.

While I’m absolutely positive that there is more to it than that if you choose- i did buy the modbus cable from pwncnc just because it wasn’t much more than buying the connectors on their own- I found the entire operation to be remarkably simple. And believe you me, given the way people act about the things, I was nearly anxious about it the first time I turned it on!

So, can you do a few decent soldering jobs and cut some wire? If so, I’d save some money and buy a kit. If something is wrong with it send it back to amazon.

My total cost to get my spindle up and running ended up being under $300. I did also buy a small industrial cooler for $120 later that is honestly totally unnecessary. I like to support small businesses and i have bought a few odds and ends from pwncnc (their dust collector maglock 3d print models are fantastic by the way) but that is just IMO too much to pay for the convenience of fixing up a few wires and following some step by step programming. I have not personally had issues with interference / emi- YMMV.

It is odd that there is relatively little good information on the spindles, and odds are much of the “ratings” they reach are bunk. But even the 800w ones will outperform a trim router.

I don’t have a lot of technical knowledge about the spindles- but i have had no issues in use.


Thanks for the info. I also do it for a hobby. I like the kit for the plug and play aspect. But…its a big investment. If i could save that kind of cash, i can do the research.


I think @Echd hit the nail on the head. Bottom line is if you have the time, you can save some cash and build your own kit similar to the PwnCNC kit. If not, sure is nice to plug everything in and go, which is what I did. I think you can also buy cable assemblies from PwnCNC if that’s of interest.

Also keep in mind that VFDs require some special safety precautions. Buildbotics has a good YouTube video on set-up. Masso also has one that discusses safety in more detail.


I have the PWN spindle no issue so far.

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I was very interested in your post, great info. I was trying to figure out how much of a premium I would be paying to get the “kit” from PWNcnc vs buying the discrete components. I am very familiar with “solar string inverters” which are really just a VFD in disguise so there is no magic to me. Having said that I do like to support small business provided there is some degree of value to me ie. pre-wired, support etc. However I was a bit put off by the “Kool connectors” they were pushing for $100 a pair. They refer to them as “custom built for PWNcnc” but I really doubt that as the instruction video says that the spindle has a M8x1 thread and they are supplying the connectors with a M8x1.25. They tell you to be very careful and just get them started before putting a wrench on it and tightening it up until the o-ring compresses against the body of the spindle. Where I come from that is called “cross threading” plane and simple. Considering these are a “one time” installation, a low pressure system I am sure it works but not very elegant and way over priced in my opinion for what I would call a “Rube Goldberg”. This has caused them to loose some credibility in my eyes. I am just about to pull the trigger on a Elite Forman for delivery in the fall of this year. Did you go with the 1.5Kw unit? I am thinking of going with a water cooled 220V version of the 1.5Kw but wondering if I should go with the 2.2Kw in order to future proof my set up. Any feedback is appreciated. Cheers John

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Hey John,

independently of the power selection, I would recommend the 80 mm spindle because with 65 mm, it’s very tight inside. You have the squirrel-cage rotor, then the stator coils and then the water sleeve. That fits better into a 80 mm housing. Also with 80 mm spindles, you have the choice of ER-16 and ER-20 collets, the latter accomodate tools with 13 mm and half-inch (12.7 mm) shanks.

HFS-8022-24-ER20 2.2 kW 24,000 rpm water-cooled


Thanks Aiph5u Good advice for sure. I was planning on the 80mm mount and will order an adaptor as I have a couple of the makita routers in my shop and will use one initially just to get up and running and some practice. I will then order the spindle (80mm for sure) as I agree with the points you raised. My reasoning for the water cooled is that I have read that the air cooled tends to run counter to the dust collection especially with the MDF and hardwood fine particulates.


Even at retail for the spindle kit you’ll save probably $450+. A 2.2KW from pwncnc is $975 before shipping. A Huanyang Kit from Scamazon costs $375. The parts you will need to accompany your Huanyang kit are a length of suitable four wire cable (preferably shielded) and a donor cable for the VFD to the wall. Maybe $50-60 worth if you go crazy with a high quality shielded cable.

I did buy some more flexible tubing at Lowes for about $10, so I guess we’ll throw that in too. Sounds like you’re comfortable with the work, so I’d go for it. The “setup” is as simple as I indicated- you will solder five points on the spindle and cable (attach the aircraft connector at four points and open the top of the spindle and run a short length of ground wire to the interior of the spindle body as for some reason the Chinese don’t believe in grounding energized equipment). They are relatively small points to solder but absolutely not difficult. After that, attach the cables to the VFD in the order dictated by your power supply. The programming is very simple but will vary slightly depending on if you want to control the spindle through the onefinity controller via modbus or just manually spin it up and based on the spindle power and voltage you buy. You can send manual commands via gcode if need be even if modbus communication is enabled. You will change the location of one jumper pin on the board (easily accessible and clearly marked when wiring) if you are using modbus.

I am currently using a 110V 1.5kw motor and the most amps I have EVER seen it draw is around 9, and I was really hauling butt with it at the time (1.5 inch surfacing bit in hardwood). I am pulling cable this weekend to run 220 to that area mostly just because I want an ER20 collet and a presumably higher quality spindle. I went with the one I have because I got a killer deal (amazon return for next to nothing). Honestly I wonder if it’s really possible to find many jobs that would work on a onefinity and cause a spindle to pull 2200 watts? It would have to be a lot of material being removed quickly in seriously hard material. But it’s better to have capability than to not when the cost is essentially the same.

The user experience with a spindle over modbus compared to a trim router is very high. A coworker’s daughter is into a local robotics club and when she found out I have a CNC they fieldtripped to my garage. The kids were thrilled to make simple signs in Vectric and watch as the machine spun up on its own and took care of business. Not that something so small as not having to toggle the switch on a makita is worth that much, but it certainly is nice to have. It is also much, much quieter. When not cutting it is a dull whir at most. When cutting it gets loud depending on what you’re cutting, but a 1/8 shank bit is not “noisy” unless it’s really hogging hard.

Perhaps interference- which the PwnCNC unit takes great care to advertise mitigating- is an issue for some, but it hasn’t been for me. I am using shielded cable and grounded components which I imagine is plenty, but I had more issues by far with EMI with the makita trim router- if it passed too near the monitor, it could cause it to lose signal. Not so with my spindle.

I would encourage the Huanyang or similar, and again, if something is jacked up with it- Amazon will take it back, so I don’t see much risk. The volume of work involved is just so low that you’d have to make a whole lot more money than I do to justify the pwnCNC kit- they’re all just chinese spindles after all.

Edited to add: You will need to either make or buy a modbus connector if you want the unit to communicate with your onefinity directly, which I would personally again recommend. It’s just two wires if I recall, but when I was looking for the connectors for me it was practically the same price when shipping was conisdered to just buy it from PWNcnc. So I did that.


Hey John,

the main argument for water cooling is that the cooling power is completely independent from spindle rotational speed. The cooling pump can even stay running a few minutes after spindle was stopped, to prevent overheating after the spindle was stopped.

This is not the case with air-cooled spindles, which have a fan on the shaft which rotates with the speed of the shaft (i.e. slow on slow speeds, and are unahle to take care of spindle temperature).

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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.