Spindle Speed Controller Question

[Boyan Silyavski]

Actually, pumps can fail, they have indeed elements that can fail, but they don't rotate as fast as a fan in the spindle. Anyway, I have so far not heard of fan failure in these spindles. It can happen, I know that, but in really... anything can break, even a water cooled spindle or a pump.

Even so if you are not milling steel and pushing it to its limits the spindle will NOT fail. It will heat up to ~60C, hot to the touch, but will continue to happily cut normally wood or light cuts in aluminum. It happened to me a couple of times when i was testing the new machines and the relay was not connected, so i had to manually turn on the pump. No smoke or whatsoever.

[JAZZCNC]

Even so if you are not milling steel and pushing it to its limits the spindle will NOT fail. It will heat up to ~60C, hot to the touch, but will continue to happily cut normally wood or light cuts in aluminum. It happened to me a couple of times when i was testing the new machines and the relay was not connected, so i had to manually turn on the pump. No smoke or whatsoever.

I'll Confirm and Back up this. For Jobs less than 30-45 I don't bother connecting the hose pipe and I exclusively cut Aluminium. Also like Boyan unknowingly due to my error I've cut jobs lasting 2hrs+ without water being on and not had any issues. Take the Fan off your air cooled spindle and watch it melt down in 10mins.!!

[Ger21]

I've used high quality air cooled spindles for years with no issues, running 8-10 hours a day, 6 days a week. HSD spindles with electric fans for over 10 years at a previous job.
At my current job, we have a 10HP spindle that's cooled by the dust collection airflow. It's been running full time for over 8 years now.

I own a couple air cooled chinese spindles, but haven't used them yet to see how long they'll last.

[JAZZCNC]

I've used high quality air cooled spindles for years with no issues, running 8-10 hours a day, 6 days a week. HSD spindles with electric fans for over 10 years at a previous job.
At my current job, we have a 10HP spindle that's cooled by the dust collection airflow. It's been running full time for over 8 years now.

I own a couple air cooled chinese spindles, but haven't used them yet to see how long they'll last.

Yes Gerry but that's not comparing Apples with apples. High quality Air cooled HSD spindle is different Animal to the cheap Air cooled what's been talked about here.
In my experience at the price level of the WC spindle NOTHING comes close to comparing and only fool would buy Air cooled at or very close to same money has WC.

[Rye]

I have a shonky Chinese 6040(any luck i'll be upgrading soon) that's falling to bits at the seems, but the 1.5kw WC ER11 spindle works a charm. Often have it running for 8 hrs solid and it only just gets warm to touch. Very quiet too - although the same can't be said for my pump(gets hot and sounds like a foghorn; anyone recommend a relatively cheap and "silent" one from ebay UK, would be grateful.) Would definitely recommend a WC over an AC - but get one with a larger collet than ER11.

[Neale]

I use a Whale submersible pump, designed as a pressure pump for fresh water for caravans, etc. Says max run time 15 mins at 12V, but I use 12V to purge the air at the start of a session then switch to 5V and it runs silently and happily for hours on end. Sits in a bucket of water and connects via cheap pvc tubing. Cost about a tenner, about 4 years ago, and still running fine.

[A_Camera]

Yes Gerry but that's not comparing Apples with apples. High quality Air cooled HSD spindle is different Animal to the cheap Air cooled what's been talked about here.
In my experience at the price level of the WC spindle NOTHING comes close to comparing and only fool would buy Air cooled at or very close to same money has WC.

Only a narrow minded fool does not understand that different people have different needs. Money is not an issue in my case, has NOTHING to do with why I prefer air cooled.

[A_Camera]

I've used high quality air cooled spindles for years with no issues, running 8-10 hours a day, 6 days a week. HSD spindles with electric fans for over 10 years at a previous job.
At my current job, we have a 10HP spindle that's cooled by the dust collection airflow. It's been running full time for over 8 years now.

I own a couple air cooled chinese spindles, but haven't used them yet to see how long they'll last.

Air cooling in itself is not negative, except in the narrow minds of some people. Water cooled is a buzz word among hobby CNC machinists today, everybody wants it regardless if they really need it, and some preachers are chanting about it like if it was best thing after sliced bread. As far as I understand, the only real advantage of water cooled spindle is the possibility to run the spindle at very low speeds, and/or for very long periods non-stop. On the other hand, if that is necessary then these cheap Chinese 24k RPM spindles are the wrong choice anyway. Many people use spindle noise as an argument, but that is only valid for those who are always milling air. Blowing around of dust may be an issue for those milling MDF or wood, but that's only an issue for those who don't have any dust extraction, which in my opinion is just as important with water cooled as it is with air cooled spindles, at least if you are milling wood or any other dusty material. Yes, the fan inside can break, but so can even the cheap bearings (which is more likely to break at high speeds) or the water pump, or the water sealing gaskets inside the spindle or the joints or whatever else.

BTW, I checked at the HSD spindles and interestingly, most smaller power air cooled have the same kind of built in fan as the cheap Chinese spindles we are talking about. Only a very few have active cooling with electric fans. Also interestingly, most of their motors have a large gap between rated and maximum speed, so calling these cheap Chinese motors 24k RPM motors is a bit wrong, even here, regardless if we talk about the water or air cooled ones. I think my assumption earlier that these cheap motors should not be run at speeds higher than 18-20k RPM, at lest not for long, was about right if even the more expensive ones have 18k rated RPM. Yes, they may work at 24k as well, but they are not designed for that. So, while water cooled has it's advantages, I don't think it is necessary for everyone, and definitely not for me. I have used my air cooled DC motor for about a year now, and never once I thought "...oh, I only wish I had a water cooled spindle" so I should know and understand my needs by now. Never the less, if my current cheap air cooled spindle would die, I'll have a closer look at HSD, or some other quality air cooled spindles, so thank you for the information. I know the price is about the same as my CNC costs, at least for some of them, but hey, this is my hobby and we live only once...

[Clive S]

I see that you are still trashing this post by Thomas just like you did with the another one.

It is not good manners to take a thread so far off course why don't you start a thread of your own.