New member intro with spindle questions!

[Dave33]

If you go for water cooled you must also add the weight of the cooling water circulating in the system, so a 2.2kW water cooled motor + motor holder + cooling liquid is probably too much for you. Also, don't underestimate the weight of cables, especially if you are going to use good quality shielded cables.

In my opinion, you should go for a 1.5kW air cooled with at least ER16, unless you are absolutely sure ER11 is enough for you. Those motors are lighter, and noise wise you can't compare them with a Kress or your Makita router. These motors are quiet (sort of), even at 24k rpm. Anyway, while water cooled are surely more quiet, the cutting noise will take over and bring it to the same or similar level when used for real work.

If you want to listen to my motor you can do that in this video.



Note that in the video, the VFD fan noise is almost always louder, and also that I made a mistake, had the microphone gain too high during the recording. So in reality, the spindle (when cutting air) is surprisingly quiet, compared to many other machines, like an angle grinder or a Dremel, and definitely all the routers I have ever heard.

It is an air cooled, 65mm diameter with ER11, and the only thing I'd change if I had to start over is that I'd buy a motor with a square house and an ER16. I'd still use air cooled.

I was just about to order some aluminium and a set of linear rails to beef up my axis to take a beast of a 5kg water spindle, but I must admit your setup looks beautiful.

Just one question does the output of cooling air from the bottom of the spindle blow chips around the workshop or do you have an extraction system that can keep up with the draft ?

[A_Camera]

I was just about to order some aluminium and a set of linear rails to beef up my axis to take a beast of a 5kg water spindle, but I must admit your setup looks beautiful.

Just one question does the output of cooling air from the bottom of the spindle blow chips around the workshop or do you have an extraction system that can keep up with the draft ?

Beefing up is always good. The more rigidity the better. But of course, it means more mass to move around...

I guess your intended 2.2kW spindle will be more like: 5kg spindle + 1.5 kg motor holder + about 1 kg water + cabling... with an air cooled 1.5kW you should save about 3 kg (less weight for the motor and no water).

Regarding the much discussed dust, I don't think it's an issue at all, but yes, I have a vacuum cleaner attachment so when I feel I need dust extraction (like PCB milling) or want to keep everything neat then I use it. I have my CNC in an ordinary room with parquet floor and which serves me as a hobby room / home office / electronic development centre, not in a workshop but dust is not a problem. I'd worry more about leakage than the dust. I mostly mill aluminium, plastics and PCB, never really any wood, but even if you mill wood, it is not the actual fan blowing which might cause dust, but the cutter spinning at high speed. Never the less, dust shoe is a must according to me, regardless if you use air or water cooled spindle. Milling makes a lot of mess, and even if I used mine in a proper workshop I'd prefer using a dust shoe and the sides covered. Anyway, I have been using this spindle for over five years and I can not see that there would be any advantage in using water cooled spindle so, I will definitely never buy one. Installing a water cooling system is also more complicated than leaving it out, and I am not keen in leading water through the same cable chain I am leading live electrical wires through. Electricity and water don't mix well... but I know many people will claim that if you know what you do then there are no risks.

...that said, I think you should carefully consider the choice you are making. My solution and needs may not fit your requirements. If you plan running the spindle H24/7 then water cooled should be the best. Also, not all motors are the same, and maybe the inverter plays a role also when it comes to how hot the motor gets or how efficient it runs. Of course, what you mill and how fast you spin the spindle also counts. The longest I run mine was about 3 hours non-stop, and the slowest I think was 4500 rpm for drilling in aluminium.

[JAZZCNC]

I guess your intended 2.2kW spindle will be more like: 5kg spindle + 1.5 kg motor holder + about 1 kg water + cabling... with an air cooled 1.5kW you should save about 3 kg (less weight for the motor and no water).

I could get into this deeper and tell you why you are wrong but I won't other than to say the water in the spindle is minimal, less than a cup full, so water weight isn't an issue.
The cooling comes from continuous recirculation of the water and provided the water container is large enough the spindle doesn't need a large volume of water around it.

Also, the 1.5Kw WC spindles are around 3Kg, not 5kg which is roughly the same weight as the Air-cooled. Cabling doesn't come into it because the Air-cooled still needs cable.

[A_Camera]

I could get into this deeper and tell you why you are wrong but I won't other than to say the water in the spindle is minimal, less than a cup full, so water weight isn't an issue.
The cooling comes from continuous recirculation of the water and provided the water container is large enough the spindle doesn't need a large volume of water around it.

Also, the 1.5Kw WC spindles are around 3Kg, not 5kg which is roughly the same weight as the Air-cooled. Cabling doesn't come into it because the Air-cooled still needs cable.

I expected there should be more water, at least around one litre, but if you say no, then I believe you. Yes, a 1.5kW water cooled and a 1.5kW air cooled has the same weight, but the discussion earlier was about a 2.2kW spindle, which is around 5kg.

You are right that the cable and the motor holder is the same, which is why I left that out of my "weight saving calculation" but my point with that was that when he calculates the new total weight he can't just look at the weight of the spindle, he must think about the rest also. While the cable is the same in all cases and makes no difference if it is for water or air cooled, it adds some extra to the weight which must be handled. But sure, if there is only a cup of water then it makes no difference for the total weight.