[wmgeorge]

I have decided to go to a air cooled (preferred) or water cooled spindle for my machine, in the future. So what Hp or Kw are you using for the deep or long running jobs?

Looking at this one.... https://www.amazon.com/Air-cooled-24...E6V7C1MD8JAG9M

[difalkner]

I went with a 3kW water cooled but a lot of folks use 2.2kW with no issues. The only drawback I've read on using an air cooled spindle is if you ever need to run longer jobs at low speed the spindle doesn't cool itself properly. I've read you need at least 12k rpm to adequately cool them. Water cooled will run forever at 6k rpm with no issues.

Again, though, that's what I've read (in several places) and have no experience with an air cooled spindles other than I've seen a few. In two years I've only run our water cooled spindle at 6k rpm one or two times.

David

[wmgeorge]

My router would more than likely Never run below 12,000 Rpm. I am wondering what the noise level would be and how they handle the dust and chips? I am assuming the housing fan just draws air over the outside of the actual finned motor, but I don't know? Thanks for the reply David, I know your busy.

[ger21]

A square bodied spindle like that is actually a round spindle inside an extrusion. The cooling air flows through the extrusion, not the motor itself.

[wmgeorge]

A square bodied spindle like that is actually a round spindle inside an extrusion. The cooling air flows through the extrusion, not the motor itself.

It looks to be the one CNC Router parts is selling but for $400 less or so.

[GME]

So what Hp or Kw are you using for the deep or long running jobs?

I'm running a 2.2kw water cooled. It has handled everything I've thrown at it, so no complaints. I don't have any experience with air cooled.

Gary

[wmgeorge]

I'm running a 2.2kw water cooled. It has handled everything I've thrown at it, so no complaints. I don't have any experience with air cooled.

Gary

Thanks Gary, can you cut 3/4 inch ply with one pass? Just wondering a guy is asking about speaker enclosures he wants cut out.

[ger21]

One thing I'd be concerned about with that spindle is it's only rated at 6 amps. The round air cooled spindle I have is 8 amps, and most water cooled are 9-10 amps.
I would expect a 6 amp spindle to have less power??

[GME]

Thanks Gary, can you cut 3/4 inch ply with one pass? Just wondering a guy is asking about speaker enclosures he wants cut out.

In a word, yes. I've never tried it on purpose, but I had a screw back out on my Z axis coupling, which allowed Z axis to drop down too far - through the 3/4" plywood and into my spoilboard. Ugh. My feed and speed was way to low for that depth of cut, but it still handled it. I've cut a fair amount of hard maple, and the spindle handles it well.

I generally cut in multiple passes at higher speeds, rather than one deep pass at a slower speed. When I push cut depth, I tend to get poorer cut quality. I usually set my feeds and speeds using G-Wizard, which I find to be a great help. It allows me to play with theoretical feed and speed combinations, and rough vs smooth cut quality. Taking theoretical to practice, it seems generally spot on. As an example, I ran 3/4" plywood through G-Wizard with a 1/4" mill. For a decent cut, 12,000 RPM gives be aboout 51 ipm. The bit deflection is .0007", which is okay, but more than I like. If I bump the speed to 20,000 RPM, I get about 85 ipm and the same deflection. If I reduce the depth per pass to 1/4", I get about 65ipm @12,000 rpm and only .0003 deflection. At 20,000 rpm, I get 104 ipm with the same deflection. I'm probably missing out on shorter overall cut times, but it works for me. I've never broken a bit, and haven't had any issues with bit chatter. G-Wizard has saved me a lot of time with trial and error settings and test cuts.

I hope this helps with your decision.

Gary

[ger21]

The bit deflection is .0007", which is okay, but more than I like.

If you think you can cut to better than .0007", I think you are mistaken. I would expect there to be more flex in the machine than that.

I also think those numbers are nowhere close to what you should run a 1/4" spiral. You'll get terrible tool life at 20,000rpm and 85ipm.

I tend to cut at about 125ipm and 12,000 rpm. And depending on material, 300-400ipm at 18,000 rpm.

[difalkner]

I cut Longworth chucks to sell on Etsy and have cut about 55 of them, all out of 1/2" Baltic Birch. I'm using a Whiteside 1/4" downcut spiral at 18k rpm, feed is 175 ipm, and depth of cut 0.20". When I finish cutting each plate the bit is not much above room temp and I can handle it with no problem. It's creating corn flake chips, not dust, and there's never any burning. Just a comparison...

David

[PLJack]

I'll chime in.
I do have an air cooled spindle. 24krpm,2.2Kw, 8 amp. Haven't really thought about it until this thread but until recently I ran it a 150Hrz or so. Lately I've been running at around 250Hrz. What ever the sound of the cut tells me really.
Anyway 150 is a good deal under 12krpm and it's always slightly warm to the touch. Nowhere near hot. Even after a 4 hour job.

Thanks.
Jack.

[GME]

If you think you can cut to better than .0007", I think you are mistaken. I would expect there to be more flex in the machine than that.

I also think those numbers are nowhere close to what you should run a 1/4" spiral. You'll get terrible tool life at 20,000rpm and 85ipm.

I tend to cut at about 125ipm and 12,000 rpm. And depending on material, 300-400ipm at 18,000 rpm.

Yeah, I get it on tool life. I rarely ever cut at 20,000 rpm. It was just an example. Also, note that I prefaced the numbers as being at a decent cut. G-Wizard has a slider for cut quality ranging from 1% for fine finish and 100% for aggressive rough cutting. I think I was using about 28%. Here's a screen shot that shows your 12,000 rpm at 125 ipm. I probably didn't use the best examples, or I should have explained the cut quality slider. My bad. Anyway, G-Wizard appears to validate your experience, although it does show bit deflection of .000862.

Just to be clear, the .0007 bit deflection I gave was directly from G-Wizard, i.e., I read it directly from the screen. I didn't make it up. I could be that G-Wizard is wrong, but it is way beyond me to make that determination.

Thank you for your practical advice.

Gary

[wmgeorge]

Gerry and others, where did you get the 8 amp 2.2 Kw spindle? When I was a electrician, rule of thumb on a 3 phase motor at 230 volts.... 3 amp per Hp. Now this is not inverter or VFD amps measured as when you go above 60 Hz the clamp on ammeters tend not to be accurate, maybe my Fluke is now but I am talking in the olden days when Tom E. and I used to wire together. He seemed to like the DC stuff for some reason?

[ger21]

https://www.amazon.com/Spindle-Engraving-24000rpm-Suitable-Processing/dp/B072FRD77K/ref=sr_1_9?ie=UTF8&qid=1540338105&sr=8-9&keywords=RATTMMOTOR+spindle

https://www.ebay.com/itm/USA-2-2KW-2...MAAOSw8GtZQ4AG

[ger21]

It looks to be the one CNC Router parts is selling but for $400 less or so.

CNC Router Parts sells this one.
GMT Air Cooled CNC Spindle 2.2kW 220/380V 24000 RPM S | Air Cooled Spindles

[difalkner]

I'll chime in.
I do have an air cooled spindle. 24krpm,2.2Kw, 8 amp. Haven't really thought about it until this thread but until recently I ran it a 150Hrz or so. Lately I've been running at around 250Hrz. What ever the sound of the cut tells me really.
Anyway 150 is a good deal under 12krpm and it's always slightly warm to the touch. Nowhere near hot. Even after a 4 hour job.

Thanks.
Jack.

150 Hz is 9k rpm
250 Hz is 15k rpm

David

[wmgeorge]

Ok on the Round Ones, I only see a round 4 pin plug. Whereas the square has not only those, but other connections for ?

[ger21]

There are only 4 wires on all chinese spindles. U,V, W and ground.

- - - Updated - - -

And be aware that on most round spindles, the ground wire is not usually connected.

[wmgeorge]

There are only 4 wires on all chinese spindles. U,V, W and ground.

- - - Updated - - -

And be aware that on most round spindles, the ground wire is not usually connected.

Acturally the Square drive ones have two wires connected to an internal thermistor. If the motor is not double insulated it needs to be grounded in some manner.