Total Newbie trying to figure my base requirements.

[bobby milam]

I sent you a PM with some info on my machine.

[Biff Phillips]

I would not recommend a water cooled spindle, although they are functional.
An air cooled spindle is much better.
I have used both.

An air cooled one typically weighs less (in my case, the difference was about 20 lbs). Less weight on the gantry is good. In a watercooled one, you have to rig up something to pump coolant through it.. In my case, I got a pump system similiar to what they use for water cooling CPUs. It is an added expense, plus I had to rig something to put it on top of the carriage that slides on the gantry (not too hard since my CNC was DIY, but still a hassle. Other people have the pump in a bucket, pump water through the spindle and drain back into the bucket, but that seems a like a pain.. imagine your router moving around, you have to worry about the hoses moving along with it and making sure they don't catch hold of something or kink, etc..

Air cooled is way better. My air cooled chineese spindle had a rectangular body on it, with holes already threaded to attach to the Z slide. This is fantastic, as you don't have to buy a spindle mount and also it keeps the spindle closer to the gantry, which is also desirable.. However the downside is that you have to drill holes into the plate that normally holds the spindle mount..

Good luck, hope what I posted makes sense..

[David Buchhauser]

I would not recommend a water cooled spindle, although they are functional.
An air cooled spindle is much better.
I have used both.

Hi Biff,

I have a 2.2 KW (3HP) air cooled spindle on one machine and a 3 KW water cooled ATC spindle on another machine. In my case, the benefit of the water cooled ATC spindle is the automatic tool change feature. This allows for much faster tool changes than with the air cooled spindle, and if implemented - fully automatic tool changes under program control. This feature eliminates the need for using wrenches to remove and replace the tool or tool/collet assembly, and then setting the tool height offset value every time a different tool is required as part of the program. The water lines, air lines, and tool holder release control wires are all run in the same cable tracks as the other cables for the motors, proximity sensors, and spindle power cable.

There are some things I like better about the air cooled setup, and others that I more prefer with the water cooled setup. At least in my case, I do not believe that "air cooled is way better".

David

[bobby milam]

There are trade offs between water and air cooled. Air cooled are generally more expensive, water cooled you have to use water. My machine came setup with water cooled and hoses are run thru the tracks so movement is not an issue. I use a 5 gal bucket with a lid and a pond pump. Once setup it really isn't an issue.
Just like David, I have upgraded to an ATC spindle so cost of water cooled and air cooled came into play. Plus if I ran an air cooled With the ATC I would have to purchase a larger air compressor to have the air flow to cool the lowest bearings so that's another expense.

These spindles are basically throw away spindles so i don't mind saving money. There is the issue of weight depending on your machine and what it can handle. The weight isn't an issue for mine.

[Jim Becker]

Just to be clear for folks new to this, air cooled or water cooled is not connected to any automatic tool change feature. Both spindle types are used with ATCs. It just so happens that a previous poster has two machines; one with an ATC and one without an ATC. It's just coincidental that the ATC machine has a water cooled spindle. ATCs are really nice to have, but they are not an inexpensive option...extra hardware, more expensive spindle because of the need to support the quick change inserts, often higher licensing fees for the CNC control software (depending on which software a machine uses), etc. Some of us have what I call the "poor man's ATC"...which is change the tool with your hands but the machine auto-measures it, or in some cases, a machine with multiple motors on the gantry, such as Camaster's X3 system with three. Most machines with ATCs are larger setups where "time is money". There is growing interest in ATCs for smaller machines, however. Gary Campbell has done a few really nice, small bed machines with ATCs and kick-butt performance for his clients.

[ChrisA Edwards]

Thanks, as the OP, this is all very educational, keep it coming.

I've been looking at the Axiom Pro series, if I move ahead with actually buying a machine, I like the flexibility of having a 4th axis capability as well as a laser engraver.

Again, my desire to own one of these is purely from a hobbyist standpoint.

[David Buchhauser]

Just to be clear for folks new to this, air cooled or water cooled is not connected to any automatic tool change feature. Both spindle types are used with ATCs. It just so happens that a previous poster has two machines; one with an ATC and one without an ATC. It's just coincidental that the ATC machine has a water cooled spindle.

Yes Jim - you are correct that the ATC feature is available on both air cooled and water cooled spindles. The reason I went with the water cooled ATC spindle was that I could not find an equivalent air cooled ATC spindle that would meet my criteria with respect to weight and cost. At the time, the smallest air cooled ATC spindle I could find was rated at around 5 KW and weighed around 60 lbs. I don't need that much power and 60 lbs. is probably way too heavy for my particular machine, particularly for rapid acceleration/deceleration moves. The 3 KW water cooled ATC spindle I selected weighs around 30 lbs., is more compact, and was much more reasonably priced. My only reservation was the narrower spindle speed range of 12000 to 18000 rpm compared to the spindle speed range on my 2.2 KW air cooled unit of 8000 to 24000 rpm. Since this particular machine is set up for machining aluminum with coolant (no wood routing) I would have appreciated having those lower speeds (8000-12000) for my application.

ATCs are really nice to have, but they are not an inexpensive option...extra hardware, more expensive spindle because of the need to support the quick change inserts, often higher licensing fees for the CNC control software (depending on which software a machine uses), etc.

For my particular machine, the ATC upgrade cost was about $1200 over and above the equivalent non-ATC air cooled spindle on my other machine. This upgrade cost includes an assortment of NBT-30 tool holders, ER25 collets, coolant system, and spindle mount adapter. The CNC control software I am currently using (Centroid CNC12 and Mach3) both facilitate automatic tool change operation at no additional cost.

David

[David Buchhauser]

There are trade offs between water and air cooled. Air cooled are generally more expensive, water cooled you have to use water. My machine came setup with water cooled and hoses are run thru the tracks so movement is not an issue. I use a 5 gal bucket with a lid and a pond pump. Once setup it really isn't an issue.
Just like David, I have upgraded to an ATC spindle so cost of water cooled and air cooled came into play. Plus if I ran an air cooled With the ATC I would have to purchase a larger air compressor to have the air flow to cool the lowest bearings so that's another expense.

These spindles are basically throw away spindles so i don't mind saving money. There is the issue of weight depending on your machine and what it can handle. The weight isn't an issue for mine.

Hi Bobby,

I am curious why a larger air compressor would be required to run an air cooled spindle. My air cooled spindle has an integral electric cooling fan that forces fresh air thru the spindle. The other air cooled spindles I have looked at seem to also have an electric cooling fan. Have you seen any that use compressed air (as opposed to an electric fan) for the spindle cooling?

David

[bobby milam]

Not sure about all but many of the air cooled atc spindles use both. The electric fan but they also use air from the compressor to cool the lower ceramic bearings. It's something like 6-7 cfm around 35 psi I believe. It's enough that people with a60gal tank say it cycles the compressor every 15-30 minutes.

Yours isn't an ATC is it? That would be why different bearings I guess.

Im not an expert on air cooled spindles but when I was shopping for the ATC that it's what my research found. I would have preferred air cooled but not at their cost like you had found

[Biff Phillips]

It all depends.. I have a Chineese air cooled spindle. It is 3 phase, I can't remember the KW, but it has similar power and cost to the cheap water cooled spindles.. both were approximately 200-300.. plus the cost of the VFD if you don't have 3 phase. I am just a hobbiest, cutting wood only.

My air cooled spindle is purely fan cooled , no compressed air needed. Will it last as long as a water cooled one? I don't know, but I am just a hobbyist, It has lasted well over 5 years now, so I am happy.. A cnc will run a router/spindle harder than using a router by hand.. lots of stuff can take hours to cut.. So no matter which way you go, you have to realize they will eventually need replaced.
Again, I am a hobbyist. I have no need for an automatic tool changer.. I just don't do the volume to justify it.. I am doing this for fun, a few minutes to change the bit is no big deal for me.

I guess I should have said FOR THE WOODWORKING HOBBYIST, an air cooled spindle is better. The OP said his budget was 2500, he's not going to get a CNC with an ATC for that price.

[Jim Becker]

Biff, almost all of these spindles, air cooled or water cooled, are three phase which is needed for the variable speed and is also better suited to the task. Traditional routers used by some machines are certainly an exception, but any speed control is manual and done differently than with a spindle. The air requirement isn't necessary for a non ATC spindle other than for a counter-balance on the Z-axis to take load off the steeper or servo from the weight of the spindle. And that's just fixed air pressure...no real "usage". (My machine is so equipped) ATCs, however use air for the quick change mechanism clamping and some use additional air to supplement cooling as has been noted and there is some level of CFM required to support that, not just a particular air pressure as with a counter-balance.

[ChrisA Edwards]

just and update on y original post, I have now decided that if I am going to buy a CNC machine, it will be in the $6K to $12K range, otherwise I won't bother. I'm going with the "Buy your second machine first" philosophy.

[Jim Becker]

Chris, that budget will open options up to you considerably.

I kinda, sorta did that "second machine first" thing myself after starting out thinking Shapeoko and then Axiom and then small Camaster and then bigger Camaster and then bigger Camaster. Of course, I shoulda bought the next bigger Camaster in hindsight. LOL (8' would have been nice in a few cases, but honestly, I'm doing just fine with 4x4)

[David Buchhauser]

Biff, almost all of these spindles, air cooled or water cooled, are three phase which is needed for the variable speed and is also better suited to the task.

Hi Biff,
This does not mean that you need to have 3 phase power lines running into your shop to use one of these spindles. In general, a VFD (variable frequency drive) is used to convert your existing 240Vac single phase power to the 3 phase power required by the spindle. In addition, the VFD allows for adjustment of the output frequency (typically under software control) to facilitate the variable speed operation of the spindle.
David

[Jim Becker]

Thanks, David...I got distracted and didn't fill in the rest of that. My bad...