Spindle cooling system

OK, I just purchased a 2.2KW water cooled spindle for my XXL. My plan is to plumb it in a closed loop system using a 3-120mm fan computer radiator. I would like others opinion on this. Also I was thinking of using computer coolant in the system. The other option would be distilled water. Does anyone have any thoughts on that?


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Hi Gary

I user a 20L water reservoir with a small 1500L per min pond pump. I have filtered water in mine with some food dye (blue…) and radiator preserver.

Works a treat and runs for hours. I did have a much smaller tank, but found the coolant getting a little too warm for my liking on longer jobs.

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Are you sure that’s 1500L/min. That’s 90,000 litres an hour. Maybe 25L/min, 1500L/Hr?

I think I will have to have some kind of reservoir since most small pumps are submersible. Looking at a 5 gallon fresh/grey water RV tank.

Sorry 1500l an hour! It was late.

Im using a large storage box with lockable lid for mine. Don’t use a cheap one mind. When you lift 20l of water you will know why.

I think I will try 3 gallons. I’ll pump through the spindle and have the cooler on the return line and put a thermometer in the reservoir, that way I can see the temp of the water being pumped into the spindle. Also I should see more stable water temperature with the cooled water mixing in the tank. As for the pump I was just giving you a hard time. I did purchase a 75 watt pump recommended for a 2.2kw spindle, don’t know the actual flow rate.


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I’ve been doing some research on pumps. Luke, you said you use a 1500L/Hr pump. Have you ever ran it through your spindle to actually see how many Liters an hour it is really running through the spindle? From what I can find it varies wildly depending on pump, head height, spindle, amount of tubing, amount of bend in tubing, etc, etc, etc. Bottom line how much flow or what temperature should we be seeing at the spindle. And I would like to hear others opinions about this subject too.


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I can’t say I have ran a flow test, but I have had one end on the pump and the other through the system and spindle and I had a good flow rate.

After say 3 hours of running a job the spindle will be warm but not hot, the water in the tank the same.

I just received my 1.5kw water cooled spindle and VFD and will be hooking it up sometime this week and have been looking into what to use for the liquid coolant. I bought this pump, two small radiators that are ~6in x ~5in and a couple of 120mm fans. I accidentally bought two of the fan 4 packs. Don’t make my mistake if you get them. And some silicone tubing to tie it all together.

The fans are actually silent, but their air flow is really low. I bought them because they fit the radiators, but I do have some 120V fans I scavenged from a large power supply that I could slap on the radiators if needed. If they are not a perfect fit, I can whip something up and 3D print it. They are loud, but it’s not like they won’t have competition.

I have been going back and forth between using an automotive coolant with all of the additives (some needed, most not), or just de-ionized water, pure glycol and an anti-fungal / anti-bactierial additive. My shed is unheated when I am not out there, and in the winter it will drop below freezing, and I don’t want that to happen.

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I have a 1.5KW water cooled spindle that has a 65mm diameter. This way I could just use the Makita router shim adapter and put it straight into the original holder.

Here is a link to the model I got (this is the 220v version):

This has been a real good buy so far. Powerful, quiet, good RPM speeds, and customizable VFD.

I purchased a tachometer to calibrate the RPM setting on the VFD and was pleasantly surprised to see it was already accurate enough (less than +/-1%)

I added a trim pot to control speed as I didn’t like pressing the buttons.

I use a 2x 120mm PC watercooling radiator and have 2x 120mm fans on it. I have yet to wire up the fans as the water barely gets warm even after 1-2 hours of cutting hard woods. I have a small reservoir of about 2 liters of distilled water which I put a silver coil as a bactericidal agent The pump I use is an Eheim compact 600. Don’t overkill on the pump too much as the more powerful the pump the more heat it adds to the system itself. Get a good branded pump as these will have a better static head, at least one advertised that you can trust.

I pretty much went the same way. Same Amazon seller but the 2.2kw version with a 3-120mm computer radiator with 3 120vac fans, an 11 liter heavy plastic oil storage container for my reservoir and a little giant 3gpm pump and 2 silver coils. My HDZ arrives tomorrow and I will start assembly. I’m still trying to figure out pump output my total head heigh on the pump will be about 4 feet. I decided to route it with my dust collector hose instead of in the power tract. It will increase head height but decrease the number and severity of bends and the amount of flexing the tubing will have to handle. Can anyone supply me with a link for good quality VFD cable that can be purchased in shorter lengths.


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Hi Gary

I user a 1.5mm cable like this:

4 core, 1.5mm, PVC coated cable. 5m will do an XXL setup through the drag chains.


Thanks Luke. Not sure if I can order from Amazon.UK or not. But I can give it a try.

Hey Luke I found 25 ft of 16AWG good to 12 Amps. I calculate max output for a 3 phase 240vac 3HP spindle should not go above 10 amps. Next size larger all I was finding was larger way more expensive rolls of flex cable.

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I ordered this Belden cable for my 1.5kw spindle. I have not hooked it up yet, but it can handle 18A according to the spec sheet.


That’s a great choice - the shield should help with noise issues, and it should be nice an flexible.

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Actually I don’t think that’s a great choice. It’s not a flexible cable. For a VFD and motor that are stationary it would be excellent. But for something in a drag chain or anything that moves you need a very high number of very fine wires in each conductor. And the picture on the web site does not show that. Failure for your application will most likely be quick. I read the info on it but the picture just does not look like a flex cable. The solid wrapped shield will make it stiffer along with the extra layer of insulation.

It is a bit stiff, but I’ll find out how bad it is in a week or so when I think I’ll get everything assembled.

I’m looking forward to what you find out. I’m in about the same boat as you trying to figure out how to best bring the pieces together.

So, here’s what I found;

From this Belden site, it looks like this cable (Belden 29501F) is going to be the most flexible VFD cable by Belden with both a foil AND braid shield (4.4in continuous flexing radius). It is rated for up to 3.7kW @ 230V.

The “104x34” stranding means there are 104 individual strands of 34 gauge wire (0.0820in / 2.08mm) for each 14ga conductor per this chart here.

Here is a Belden document that shows you how to properly terminate it at the VFD. And in video format as well.

A google search found this place sells it by the foot with a 1 foot minimum. There may be more places, but they were the first that I found that sells it in quantities less than 1,000 ft at a time.

So, I will probably be buying some of the 29501F cable in a few days because it looks like the stuff I previously bought is not really made for continuous movement. Thanks /u/HDRyder :+1: for making me double check that. Now Hopefully I won’t have a failure in a couple of months.


What you found sounds proper. I’ve wired many VFD’s in my days and 7 strands of 24 gauge just did not sound right for flexing. However most of the one’s I’ve wires were static installations that did not move. I will probably order some too. Thanks for sharing your research.