# Do I Need A Coolant System?



## grepper

What have I gotten myself into?   This seems never ending!

Mini mill.  Do I really need a coolant system? 

If it's really necessary:

Mist?  Seems problematic.  Oily mist in the air, coating everything.
Flood?  Seems really messy.  Need to build enclosure, sump, etc.
Micro Drop?  Out of my budget.

Manually squirt cutting oil or coolant?


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## ch2co

While I usually work with aluminum and brass, the occasional mild steel etc creeps into my plans.
I typically just brush my cutting fluid on with an little brush. Not being a heavy duty milling machine,
I haven't found any need (so far) to cool things with mist or flood.  I just milled a bunch of cast iron
and found that canola oil that I got out of the kitchen worked with the least amount of smoking, stink,
and messy cleanup.  In the past, I've brushed on oil, cutting oil etc. and would still go back to the canola oil.
For aluminum, I use WD40 which has a long application tube that makes it easy to get into the 
working area.

CHuck the grumpy old guy


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## JimDawson

Yes, you need coolant, especially for aluminum (WD-40).  Just make your own microdrop setup.  Very easy to do.  An air flow control, a pressure tank, an air regulator, some fittings and plastic tubing is all that is required.  About $100 in hardware.  It is a true microdrop, no-fog system.  Runs from  zero to flood.

You could go crazy and make a full on digital controlled system, but that is way overkill. http://www.hobby-machinist.com/threads/digital-mist-coolant-pump.40405/  Sometimes you do stuff just to see if it will work.


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## Bob Korves

Aluminum:   kerosene or WD40.  Edit:  Dry works, too.
Steel:   cutting oil.
Cast iron, brass, and plastic:   dry.

Anchor Lube is very good on stainless steel and is water based, works on nearly everything, and it is thick enough to stick to taps and drills.  No smell, either.  It can be watered down as needed.


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## TommyD

Onseys twoseys, I don't see a need for anything more than a pump can of approprite lube. Production, I would consider something more. All in how much you gonna use it.

From what I have found, you NEED to wipe everything down when using an aqueous coolant. They never did here and exposed metsl is rust pocked and the paint stained where the coolant petrified.


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## Uglydog

Bob Korves said:


> Aluminum:   kerosene or WD40.  Edit:  Dry works, too.
> Steel:   cutting oil.
> Cast iron, brass, and plastic:   dry.
> 
> Anchor Lube is very good on stainless steel and is water based, works on nearly everything, and it is thick enough to stick to taps and drills.  No smell, either.  It can be watered down as needed.



Solid advice.
When I change oil in a head stock or lawn mower. I evaluate the oil if it's dark and dirty it goes in the outside bucket for oil quenching. If it is still a clearish I use it and on steel. Note: I am not recommending that you breathe the oil fumes/smoke. 

Ventilate.

Legitimate cutting oil performs much better! 

Daryl
MN


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## JimDawson

You guys do understand that we are talking about a CNC machine here?  Not a manual machine.  I have been following the rest of the threads on @grepper's posts on converting a mill.  With a few exceptions, coolant is pretty much mandatory except for very light work, and always for aluminum to prevent welding to the tool bit.


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## grepper

I'm doing this in my basement.  I guess I need to count on some kind of sump under the mill and a full enclosure so I won't end up spraying WD40 or whatever all over the place.  Right?


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## jbolt

On the big CNC router/mill we built for the high school we use only a no-mist system that I built. With the high speeds we run we had some tool welding issues so we added a second air stream and it works really well with very little mess. A quart of coolant lasts about 12-16 hrs of continuous running. Most of the material we machined this year has been 1/4" to 1/2" aluminum plate. A shop vac makes quick work for cleanup.

For your size mill you could do a simple three sided enclosure with a shallow bottom with no top or front. Just enough to keep the chips in check and make cleanup easier. On my flood coolant system I had an aluminum tray made and use pcv pipe and cheap shower curtains for the sides.


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## jbolt

JimDawson said:


> Yes, you need coolant, especially for aluminum (WD-40).  Just make your own microdrop setup.  Very easy to do.  An air flow control, a pressure tank, an air regulator, some fittings and plastic tubing is all that is required.  About $100 in hardware.  It is a true microdrop, no-fog system.  Runs from  zero to flood.
> 
> You could go crazy and make a full on digital controlled system, but that is way overkill. http://www.hobby-machinist.com/threads/digital-mist-coolant-pump.40405/  Sometimes you do stuff just to see if it will work.



Darn you Jim, that's too cool. Now I'm going have to make a pump.....


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## Al-Hala

grepper said:


> I'm doing this in my basement.  I guess I need to count on some kind of sump under the mill and a full enclosure so I won't end up spraying WD40 or whatever all over the place.  Right?



Flood coolant is needed to make high performance machining possible; carbide "hates" shock cooling from weak/intermittent cooling, deep holes/pocketing need to have chips evacuated, re-cutting work hardened metals like stainless steel leads to short tooling life so the flood clears the chips, etc. It is not mandatory in a hobby level machine. A mister/atomizer setup will require a air source, which means in a home environment, shielding the compressor away for noise reduction, or getting one of the California Air variants (trade off is they have lower lifespans). Misting does not cure the need to evacuate chips and re-cutting, however, so it is not the end-all. A lot of professionals are using "Minimum Quantity Lubrication" systems.

Jim Dawson, as usual, is has hit the proverbial nail on the head.  Here is a new term you should become familiar with: "Built Up Edge". I've referenced one YouTube link, there are others. As Jim mentioned, metal being machined welds itself to the tip, changing the cutting angle, rubbing, ripping parts of the edge away, all sorts of fun stuff. Aluminum is a "grabby" material, and lends itself to this very easily. there are coatings on tooling to help delay this, and there are some edge cases where people claim to have done without coolant/lubricant (usually high speeds and small bites), but in general, not recommended.

Check out some of the other machining videos on the 'tube; here are some excellent high speed camera shots that can show the cutting operations, note the differences in the different materials.


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## grepper

That's some amazing SEM photography!  Very cool to actually see what's happening.  It would be interesting to see the photographic equipment.

Really proves the case for coated cutters.  I wonder what coating they mean, TiN?  CrN?


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## Al-Hala

grepper said:


> That's some amazing SEM photography!  Very cool to actually see what's happening.  It would be interesting to see the photographic equipment.
> 
> Really proves the case for coated cutters.  I wonder what coating they mean, TiN?  CrN?



Yes, I found it very illuminating. The high speed photography ones are not scanning electron, however.

As to the terms, all can be looked up without much difficulty, or as previously stated, the Handbook *grin*. Try a Google search on the tooling of your choice: end mills, lathe inserts.

TiN is Titanium Nitride, a very common one. Once the coating wears off, you are exposing the bare metal cutting edge. Diamond is another. Keep in mind the coatings "dull" the edge somewhat, which has its own series of trade-offs. It is worth noting at least one type coating requires high temperatures to work effectively, which would seem counter to high volume coolant *rolls eyes*


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## grepper

Will I ever actually make some chips?


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## Al-Hala

grepper said:


> Will I ever actually make some chips?


"There is no try..." *bonks green muppet with a precision level*


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## grepper

Al-Hala said:


> Once the coating wears off, you are exposing the bare metal cutting edge.



That's exactly why I don't bother with it for with standard drill bits.  When they get dull, I just sharpen them.


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## Smithdoor

You find on large machines it just not work with coolant
I have coolant and oil on some tools but found most work did not need coolant
Some time on cutting steel I will use mist only keep the temp of chips down
On threading and some milling I will brush on oil. Most of time today I just use a vacuum my wife is happy.

Dave


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## Al-Hala

Here is a brief discussion of some coatings used on tooling inserts:  http://www.productionmachining.com/articles/a-guide-to-insert-coating-processes-and-materials


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## mmprestine

NO, Spray Bottles!


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## TomS

grepper said:


> I'm doing this in my basement.  I guess I need to count on some kind of sump under the mill and a full enclosure so I won't end up spraying WD40 or whatever all over the place.  Right?



The problem I had was not containing the coolant (I have flood on my mill) as much as containing the chips.  First couple of jobs I ran took about an hour each but I spent the better part of a day cleaning up.  I had chips spread out in a 10 foot radius around my mill.  My full enclosure now keeps my work area clean for several days of run time.  

As Jim said you do need coolant of some sort.  At first I used cutting oil and a squeeze bottle, gravitated to a no-fog mister system, then settled on flood coolant.  Each method has it's advantages and disadvantages as others have pointed out.  I prefer flood but that's my opinion.  Whatever you choose it has to work for you.

Tom S.


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## derf

No need to over think this.....it's quite simple. Go to HF and buy a fountain pump and some plumbing supplies and run it from a 5 gal bucket. Need an enclosure? try a shower curtain.
All of that will cost less than a gallon of good coolant concentrate.


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## coolidge

Been there done this on a CNC mill in a basement, here are the pro's and con's of two methods...

Flood Coolant - Pro's are cools and lubricates well. You can rig a hose and use the coolant for washing down the enclosure. Con's include short of a full and complete enclosure including the top you won't be able to run the coolant at a high enough pressure to blast the chips out of the cut which is pretty important. You are talking 250-1000 psi coolant systems on industrial CNC machines. Even at modest coolant pressures, steady stream not capable of blasting chips coolant will fling up and out the top of the machine all over the floor. You will become one with a floor mop. Your coolant drains will plug up with chips. Cleaning up the wet chips isn't a pleasant task. Your coolant will go rancid. Even with the best full synthetic coolant, aerator, and oil skimmer. It will stink and colonies of god knows what will grow and plug up the pump and hoses. Its a nasty business. At proper concentrations you won't have a rust issue with water based coolants except under a vise this area always seems to rust. The coolant leaves a sticky film on everything including your parts, that's the rust preventative.

Micro-Drop Coolant - I have an Accu-lube system. Pro's are 1 gallon of lubricant will last pretty much forever. The Accu-lube system delivers a tiny spritz of coolant droplets onto the tool and part via air, this is NOT a mist system. Air does the cooling and blasts the chips out of the way, the lubricant does the lubricating. Will never go rancid. Properly adjusted your chips will be mostly dry so easy clean up. No risk of rust ever as there is no water. The lubricant is fairly thin, it doesn't get sticky or build up. Con's include you need air and dry air no less, you don't want to be blasting your machine with water droplets. Long story short I settled on a California Air compressor, 10cfm with air drying system. Its a LOT quieter than pretty much any other type of compressor short of a rotary screw, 60-70 decibel range but noise is noise. The compressor will cycle on every few minutes during use.  But if you are talking your average gear head mill I doubt you will hear the compressor over the blasting noise the mill makes.


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## chips&more

coolidge said:


> Been there done this on a CNC mill in a basement, here are the pro's and con's of two methods...
> 
> Flood Coolant - Pro's are cools and lubricates well. You can rig a hose and use the coolant for washing down the enclosure. Con's include short of a full and complete enclosure including the top you won't be able to run the coolant at a high enough pressure to blast the chips out of the cut which is pretty important. You are talking 250-1000 psi coolant systems on industrial CNC machines. Even at modest coolant pressures, steady stream not capable of blasting chips coolant will fling up and out the top of the machine all over the floor. You will become one with a floor mop. Your coolant drains will plug up with chips. Cleaning up the wet chips isn't a pleasant task. Your coolant will go rancid. Even with the best full synthetic coolant, aerator, and oil skimmer. It will stink and colonies of god knows what will grow and plug up the pump and hoses. Its a nasty business. At proper concentrations you won't have a rust issue with water based coolants except under a vise this area always seems to rust. The coolant leaves a sticky film on everything including your parts, that's the rust preventative.
> 
> Micro-Drop Coolant - I have an Accu-lube system. Pro's are 1 gallon of lubricant will last pretty much forever. The Accu-lube system delivers a tiny spritz of coolant droplets onto the tool and part via air, this is NOT a mist system. Air does the cooling and blasts the chips out of the way, the lubricant does the lubricating. Will never go rancid. Properly adjusted your chips will be mostly dry so easy clean up. No risk of rust ever as there is no water. The lubricant is fairly thin, it doesn't get sticky or build up. Con's include you need air and dry air no less, you don't want to be blasting your machine with water droplets. Long story short I settled on a California Air compressor, 10cfm with air drying system. Its a LOT quieter than pretty much any other type of compressor short of a rotary screw, 60-70 decibel range but noise is noise. The compressor will cycle on every few minutes during use.  But if you are talking your average gear head mill I doubt you will hear the compressor over the blasting noise the mill makes.


Coolidge, You just nailed it in two paragraphs! I have also been down the same path. The rancid smell of coolant was the last straw for me! Anybody reading your post can save a lot of grief!!!!!! You did excellent!...Dave.


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## grepper

The whole coolant issue is turning this into a different beast altogether.  I wish I had thought and asked about it at the beginning rather than the end of this.

The idea of flood cooling is disgusting.  I can just imagine dealing with it.  Everything, including the machine covered with sticky goo, piles of wet gloppy swarf to shovel up, clogged filters and drains, science experiments of rotting coolant sitting around effusing invidious effluvia, all whilst threatening to escape confinement (think the movie- The Blob), rust, and constant cleanup.  I couldn't stand to let a mess like that sit around.  I'd be spending more time in damage control than having fun.

Mist systems; somewhat the same, only somewhat less, with the added benefit of fine, oily mist filling the air and coating the entire basement with filmy slime, and the joy of spending quiet time happily machining away... next to a compressor.

MQL-Mico drop;  Much better!  Especially considering I'm already over budget on what I envisioned as a hobby.  MQL + a small, quiet compressor would bloat the cost another $800-$1,000.  I have a portable compressor I could use, but you have to shout to be heard over the thing- not appealing, and it would still cost $800 sans compressor.

I'm feeling a bit flummoxed and lugubrious about the whole thing.


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## JimDawson

Ahhhhhh, the joys of CNC.  It's really not as bad as it seems on the surface.   It took me about 2 years to implement everything.  I just built stuff as I needed it.


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## Al-Hala

Well, you could start work with plastics, wood, other materials to start with that do not require coolant. That would give you valuable experience working with the machine and basic procedures. My first items were small wooden boxes before I moved up to Aluminum, You could also fabricate a reverse-engineered variant of the Trico, Acculube, or Fogbuster systems; trade-off in time cost vs. cash cost.

Edit: I second Jim. I increased my forearm muscles the "other" way; standing sentinel with a spritzer bottle.

Here are some links to DIY:

http://www.cnczone.com/forums/uncat...nes/102934-built-fog-less-coolant-mister.html
http://www.machinistblog.com/zero-fog-mister/

http://www.cnczone.com/forums/general-metalwork-discussion/87439-cooling-hvlp-mist-producer.html


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## grepper

JimDawson said:


> It took me about 2 years to implement everything. I just built stuff as I needed it.



A coolant system does not seem to be something I could put off. I originally thought I could get into this for about $1K- the cost of a mill.  Then I knew I had to go CNC,  Bump- $2K. Bump again- $2.5K.  I expect and plan on cost overruns, that's always a given, but now I'm looking at 3X what I planned on- $3.5K.  Rather difficult for me to justify for my simple hobby use.

Any opinion on Fog Buster?  It's about 1/2 the cost of Accu-Lube and it's ilk.  From vids I've seen on it working, it appears waaay less messy. A less expensive micro drop system.  It looks like I could just put a fan on it when finished and things would dry up in a couple of hours.

I don't know fluid dynamics and would not know how to design the mixing block; hole sizes, needle valve, etc.  I wonder if just that part is for sale.  Other than the mixing block it's just a whole house water filter, some tubing and a pressure gauge.  $375 seems a little pricey for that.  But then it probably just works well right out of the box.



Al-Hala said:


> Well, you could start work with plastics, wood, other materials to start with that do not require coolant. That would give you valuable experience working with the machine and basic procedures. My first items were small wooden boxes before I moved up to Aluminum, You could also fabricate a reverse-engineered variant of the Trico, Acculube, or Fogbuster systems; trade-off in time cost vs. cash cost.



You do have a point there.  Learning on wood, plastic, etc., would have some value.  Save $$ on cutters whilst learning.   In a lot of ways, that is not a bad idea.  I could probably spend a lot of time with that and be better off for it.

But... it's putting off the inevitable.  I have little use for, nor interest in wooden stuff.  Not into Amish toys, model Conestoga wagons or ships in bottles, etc.


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## Al-Hala

Heh. Wholly agree. The boxes were purely functional; they hold tooling. I'd used wood router carbide tooling to make them.


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## grepper

Al-Hala, thanks for the links.  You posted while I was typing.  Could it be that I can keep this thing under $3K?


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## JimDawson

I built my original micro drop system for about $100 in parts if you buy everything new.  It does not need to be fancy.  Take my digital pump system, eliminate the pump, and it works just fine.  I'm using my system *without the pump right now*, I need to make some pump modifications.  No fancy mixing valves needed, just standard hardware items.  But yes, you still need an air compressor.


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## Al-Hala

grepper said:


> Al-Hala, thanks for the links.  You posted while I was typing.  Could it be that I can keep this thing under $3K?



Welcome. Heh, keeping costs down. That depends on your inventiveness and patience. In machining, the purchase of the machine is one thing; the tooling required can easily equal and exceed the cost of the machine. That was the advice I was given before I got started, and it has proven out without question.

It really is just a trade off between your or friends sweat equity and time vs. purchase. At some point you have to decide what your time is worth. For some people (myself included at one time), they want to USE the machine, not build it. Others I (like myself currently), want the (insert adjective here) of building the machine up.

When I total all my costs: machine, tooling, CNC items, enclosure, I blew past that figure quite quickly. However, I am a Canucklehead; My Petrodollar is worth a wee bit less than yours on average. Given the time period over the outfitting my dollar went from being worth more than the US to 40% less, I would still hazard I went over that figure by a fair amount (shipping costs from the US to Canada are ruinous via UPS or Fed Ex for a lot of sources; the mill added $300 in shipping alone). Others native to the US might have a better angle on answering that question.

For creative vs. purchase, my own CNC linear motion showed me (from cheapest to most expensive) the following solutions:
- Leaving the OEM leadscrews in place, machining motor mounts to fit them. The backlash is dealt with using backlash compensation in the motion controllers. The motors are sized to compensate for the inherent greater loss of efficiency in leadscrews.
- Others reduced cost via only automating two axis, and leaving the Z manual (that always struck me as a false economy; what is the point of CNC when you have to adjust an axis every few minutes)
- Purchasing Chinese sourced ballscrews, machining motor mounts to fit them. There are a couple of sources that several have used and recommend
- Purchasing a combination kit of the above
- CNCFusion LMS machine kit

I chose the CNCFusion kit due to a combination of USE the machine thinking and lack of faith in my ability to source and acquire parts and build the mounts. Today, I would probably have tackled the job, or risked the eBay route (since there are several others since claiming good results and I am more confident in my abilities as a hack machinist).

*Edit:* Sorry for the late edit, but I found another good example of thinking out of the box (there is a pun there if you watch the video) MacPod Toolbox Controller. Macpod.net is the website of a fellow who made a $50 tachometer for the LMS Seig style spindles. I have known of him for a while, but did not think to look him up on YouTube. The Video shows how he used a metal toolbox to house all of the control and power systems. Now, I am not certain I want to put power line level items (120V) that can dissipate some heat into that form factor or container, but it is a novel approach (he claims one off, so no plans).


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## Al-Hala

JimDawson said:


> I built my original micro drop system for about $100 in parts if you buy everything new.  It does not need to be fancy.  Take my digital pump system, eliminate the pump, and it works just fine.  I'm using my system *without the pump right now*, I need to make some pump modifications.  No fancy mixing valves needed, just standard hardware items.  But yes, you still need an air compressor.


I recently read through that writeup of yours, Jim. That was quite nice. I would not have thought about using a peristaltic pump, but upon reflection, it makes sense.


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## jbolt

My experience so far with flood coolant has not been as horrific as it has been made out to be but I can understand why some don't want to deal with it. In the hobby sized environment the only issue I run into with chip evacuation using a low pressure pond pump is when making full depth finishing passes in a slot or pocket and the long slender chips bunch up. For these tool passes I have the air come on in addition to the flood which helps a lot. In the two years I have been running the flood coolant it has never gone rancid or smelly. Yeah it can be messy to clean up. My only real grip with flood coolant is it's ability to strip paint but I'm not real sensitive to how my machines look. As long as they are well maintained and perform their intended function I could care less how it looks cosmetically.


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## grepper

Please prepare your self for stupid questions, cuz I'm going to embarrass myself and ask some ! 

Is there any coolant that evaporates so that chips can just be vacuumed up after it dries, or is it just the fate of CNCing that you have to wipe oily goop off everything? 

I take it just plain water doesn't cut it.

I've read about some places using alcohol.   That seems dangerous and would require some sort of forced ventilation.

Jim D.  I notice you use WD40.  Why choose that over all the coolants available?  My experience with WD40 and drilling is that it is a stinky, smokey mess.  I wouldn't think it would drain off well and would pile up in a gooky mess.

What coolant would be best with a Fog Buster?

At this point I can't really machine anything because I have no coolant system.  Plus no experience.  Currently I should probably be considering just scratching away at some balsa wood!


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## Jim_Hbar

Machining steel involves using some sort of cutting fluid - if you think WD40 is smokey and stinky, try some of the sulfide based cutting fluids  .
To play around with your mill, get some scrap blocks of UHMW and have at it..  The biggest issue then is static cling.


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## JimDawson

One thing to note is that many times we use ''coolant'' and ''lubricant'' interchangeably, and just call it coolant.  

I like WD-40 for cutting aluminum, kerosene works great also (or a 50/50 mix).  A gallon lasts for days of steady work, months with just intermittent work.  If you are cutting manually, an occasional squirt from a can works fine, but when running the CNC a steady mist is important to keep the tool lubricated so the aluminum doesn't weld to it.  Steel and other materials are more forgiving and can be run dry or with brushed on coolant.  Most times on tool steel I just run air with no lubricant at all.  It's important to get rid of the chips so you are not recutting them, this is where the air come in.  Most of my work is aluminum so I just keep WD-40 in the tank.  Most times I machine plastics dry with an air blast, but sometimes use a detergent/water mix for acrylic or polycarbonate.  UHMW and HDPE are always machined dry, they cut like grease anyway.

Cutting generates heat, so no matter what you use you are going to have some kind of vapor generated.  I have a vent system with an in-line fan if I'm really generating a lot of vapors.

There are many commercial coolants available in just about any mix you can think of.  Most mix with water, some are used as furnished.  There both synthetics and natural types.  I even have a gallon of soy bean based coolant for really small work and engraving.  I don't like the water mix stuff, I would rather clean up oily chips and I don't have rust problems.

If I were using a FogBuster, I would use the recommended coolant.  I killed my commercial mist system by ignoring the manufacturer's recommended coolant.  That's when I started experimenting with my own system.
.
.


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## grepper

OK.  I get it. Thanks everybody for your help on this last (and unexpected) piece of my, let's make a CNC machine puzzle!!!.  I may have some build questions later, but for now at least I think I'm good to go.

Interesting; well for me at least: It took me a month of research, a LOT of questions, and the seemingly endless, patient, and informed help from all of you guys to get a clue.  Hmmm...   Don't know if I should be admitting to that, at least publicly.    What a trip!


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## Al-Hala

There is too much to learn in the world for one person to get it all in a lifetime, and no need. Ask away, make an effort to search out common answers to common questions, pass the knowledge forward to others lower on the learning curve than yourself, and it will all work out. Ignorance is not a sin, unless it is willful  Then it is time for the Ban Hammah!


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## chips&more

Your air compressor(s) do not have to be in the same room. They can be in another room or even outside, if the noise from it is an issue.


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## derf

A coolant system should be the least of your worries at this point. Get the machine up and running first, then look for solutions  after you find problems. Trust me, once you get that far, the coolant dilemma will be a no brainer.


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## grepper

Sage advice I'm sure.  In fact, that's exactly what I plan on doing.  However, at least from my current neophyte perspective, I doubt the coolant thing will ever be exactly a no brainer.  Other than attaching a 1 x 10-8 mbar vacuum pump to the large hole I'm drilling in the side of my wallet, coolant seems to be the one messy, disgusting, downside to CNC.


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## Cheeseking

Grepper fwiw I run dry almost exclusively and rarely have a problem.  I'd rather avoid the mess and deal with wearing out cutters faster.   Carbide is almost mandatory if you want to cut steel dry.  HSS will smoke in no time.  
Like Jim pointed out keep the chips clear especially in slots or pockets.  A little compressed air stream helps greatly to evacuate chips and provide some cooling.   In a production setting flood coolant makes sense but for a home shop the tradeoffs are considerable.


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## grepper

I've wondered why I see so many videos of people cutting dry, even doing aluminum.  I see it all the time.  Maybe it's worth the trade-off.  I would way rather just vacuum chips than deal with sludgy a mess. 

Onion hand I tend to take Jim D.'s word as gospel, and feel lucky to have his erudite advice.  He's been at this for awhile.


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## TomS

grepper said:


> I've wondered why I see so many videos of people cutting dry, even doing aluminum.  I see it all the time.  Maybe it's worth the trade-off.  I would way rather just vacuum chips than deal with sludgy a mess.
> 
> Onion hand I tend to take Jim D.'s word as gospel, and feel lucky to have his erudite advice.  He's been at this for awhile.



I have flood coolant and a full enclosure with wash down on my machine.  Clean up is not that difficult.  When I'm done machining I wash the enclosure interior and vacuum up the chips.  Done!  I'm relatively new to CNC and maybe a bit naive but I find it easier to clean up the CNC mill over my manual mill with no enclosure.

Tom S.


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## Firebrick43

Were I work we have several hundred large 4 5 and 6 axis machines as well as dozen large surface grinders and 2 dozen 25' crank grinders.  95% of then are on water based coolant and a few deep hole drills on oil. 

We find flood coolant pretty worthless from the cutting point of view. Low pressure systems are 60 psi.  High pressure thru coolant is adjustable and can be a 1000 psi. Now this is for carbide and 20 to even 200 hp spindles.  

The flood coolant is mostly for chip evacuation.  

Con to flood coolant is rust.  If you move and use the machine every day nothing happens, but during 2-3 week shutdowns or if operator leave the grinder tail stocks setting in one setup position rust problems can get bad and expensive.  Coolant is mostly centralized but some machines is stand alone.  The coolant is checked everyday on the main systems and weekly on the stand alone. 

On some of the non production machines such as the tool room lathe the coolant can turn acidic and is not worth it in my opinion.  Eats glass scales.   Also water many times get past seals and reeks hell in servos, bearings, hydraulic systems, and gearboxes.  

The oil systems don't have any of these issues but the oil is very expensive, nasty to be around let alone work in(feel greasy at the end of the day just setting by it) and fire is a real hazard.  

Burn up a tool on a machine without load monitoring and you are not there quickly she can light up and is hard to put out. Many small shops can't use it as they can afford the insurance rates.  

We even cut dry on some milling cutters (indexable carbide or ceramic) 
Ceramics especially can't  handle the shock cooling.  Most of our slant beds also cut dry

From a home shop point I wouldn't mess will coolant as sometimes the machine will set for weeks without use.  Also without tool detection and load monitoring the advantage of coolant over operator applied cutting oils is negated as the operator needs to be present at all times or nasty wrecks will occur.


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## grepper

Firebrick43 said:


> several hundred large 4 5 and 6 axis machines as well as dozen large surface grinders and 2 dozen 25' crank grinders.



That's big!



Firebrick43 said:


> home shop point I wouldn't mess will coolant as sometimes the machine will set for weeks without use. Also without tool detection and load monitoring the advantage of coolant over operator applied cutting oils



Both manual and CNC?


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## Firebrick43

Ya, there big but it's funny how size becomes what your used to.  I can only imagine the size of machines that makes the big ship diesels.  

Unless your home machine has a tool changer, tool probe, enclosure, spindle load monitor, and thru spindle coolant I would skip it on both.  

I think a lot of people belive you can start a cnc machine and walk away.  In a production environment you do.  While your machine (or 2/3 machines) are running you are loading parts on pallets or a done machine, writing another program, or changing tools.  These production type machines need all of the above needed items to work without constant at tension. Off your missing one or more of the listed items, you probably need to be there.  If your there watching over the machine then why worry.  When the program stops and you change tools the a brush/hook,or even shop vac clears chips. When your drilling or tapping a spray bottle or oil can can be used to apply cutting oil locally which is going to work better than flood coolant(not better than thru tool coolant however).  

By all means if you have a vmc, hmc, or turning center have at a coolant system but I don't think you do if your posting here.


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## grepper

You could put my whole machine, a LMS 3990, in as a single tool in the tool holder of the stuff you are talking about.  Sure seems like at least a good air stream to keep chips clear would be in order.


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## Firebrick43

An air wedge or accelerator nozzle    would be nice to keep chips from building up in pockets and such. 

48008 or 48002 nozzles from airtx use specially designed tips that use Venturi to draw surrounding air into the tip giving more power with much less air usage and much quieter.  Make sure your put a regulator inline to adjust flow to just blow out around the tool and not send them intooblivion


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## uncle harry

grepper said:


> That's some amazing SEM photography!  Very cool to actually see what's happening.  It would be inte
> 
> Really proves the case for coated cutters.  I wonder what coating they mean, TiN?
> CrN?



SEM is scanning electron microscopy done in high vacuum.  I think the photographs are either directly from image displays or printed from digital signals according to my recollection.  Please correct me if I'm in error here.


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## grepper

Firebrick, I have zero CNC experience and am just building my first machine.  I found your post most interesting as you speak from lessons learned in very large scale, heavy industrial manufacturing.  I love the idea of not having to worry about dealing with the added expense, let alone the mess, hassle, cleaning, maintenance as well as the other associated problems you mention about coolant. 

For those reasons, I keep thinking about your and a few others advice of simply not bothering with it.  However, that advice runs contrary to the majority of sage and greatly respected recommendations that coolant is an absolute necessity, if for nothing more than chip evacuation.

While the very large equipment is in some ways similar, it is very different from comparatively minuscule home machines in speed, power and cutting tools used.  Please understand that I'm asking from a total beginner's perspective, just trying to learn before I start, and with great respect.  I'm trying to understand the divergent advice on if coolant is necessary.  Do you think your advice to not bother is applicable to teeny-weeny little machines like that LMS 3990?

Whenever I see big machine manufacturing with giant powerful machinery, it always give me sort of a special tingle deep inside.  It's so freak'n cool! And, if for no other obvious reasons, the achievement it represents.

I'm guessing your suggestion is derived from experience gained in large scale, really impressive and amazing manufacturing environments something like this:


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## uncle harry

Firebrick43 said:


> An air wedge or accelerator nozzle    would be nice to keep chips from building up in pockets and such.
> 
> 48008 or 48002 nozzles from airtx use specially designed tips that use Venturi to draw surrounding air into the tip giving more power with much less air usage and much quieter.  Make sure your put a regulator inline to adjust flow to just blow out around the tool and not send them intooblivion



I have a vortex cooler that I use when machining soft plastics.  It is capable of air temperatures as low as 40 degrees F.  They are definitely air hogs but they can save the day when needed.    Exxair (brand/Co.) makes venturi-based devices for blow-off uses including air knives and nozzles.


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## Firebrick43

Grepper, 

Having varied interest such as draft horses, farming, and woodworking  I have seen so many practices preached or practiced as necessary buy the non professional crowd.  I have come to the conclusion most of this is driven by two things.  

1. People look to professionals and take they ways that they are doing them as gospel.  Remember 1 thing drives the practices of professionals. Profit.  Many times profit means time or as little as possible to make a given product.  Technologies such as coolant, chip conveyors/systems, carbide tooling, and cnc are not the cheapest to purchase and run, but the labor savings is so great they save money and or get more product out the door in the end.  Hss tooling is very well suited for fine careful work and takes much less hp/machine rigidity to do the same job as carbide.  But the proliferation of carbide inserts in the shop is very much a product of amateurs looking at and emulating professionals even if many times it's not really the best choice for their situation.  (I am not saying hobbiest should  not use carbide, I am saying many don't really understand when and where they should or should not)

2. Diy magazines and Internet forums have advertisers. That is really how the make money.  Advertisers want you to buy their products and wares.  The editors are not going to tell you that the products they advertise are frivolous or tell you better/cheaper solutions. Also they don't give negative reviews typically unless you closely read between the line. 
. 

For example in woodworking I have seen several people want to cut dovetails. Most of the wood bucher mags show jigs and routers to do this. Some are cheap but results are terrible. Others work well but are very salty.  All the jigs require fiddly adjusments, perfectly cut/planed stock and several test cuts.  If you making a dozen plus drawers (same drawer/dimensions)it makes sense.  What hobbyist does that???  A 100$ worth of tools (hand saw, gage, pencil, chisel, and a small file    I can cut two drawers with no gaps in the joint before my neighbor gets his jig set up. And he still can't get the pleasing gap free joint or do odd spacing or very narrow tails possible by hand.  

Some of the hobbiest never step back and learn, but common think that a new, more expensive tool hocked in the latest rag is going to solve their woes of make a job possible. 

I learned this lesson very young.  At 12 my father found me a grizzled old mentor.  A retired machinist, named Jack, regaled me of an earlier time when he was an apprentice.  The man could do more with a file than many could with an entire machine shop. Not that he always did but filling a flat on a shaft was quicker than setting it up in a mill.  

Next big lesson came at 18.  Grandfather got me interested in shooting.  Father really did care for it so when I came of age I was going to buy myself a pistol.  I poured over the gun rags and all the rage at the time was glocks.  The 17c had just came out and was compensated.  I plunked down my hard earned money and couldn't wait.  Well it was terribly loud, jammed, and flames in low light blinded you. It went down the road.  I learned to not look at the current fad or listen to gun counter cowboys but watch for the quiet guys that shoot well with even ratty old guns and ask for advise.  It surprises people at a range when someone shows up with a revolver or lever action and can put rounds on target as or more accurately and as fast to boot as a good semi auto pistol or AR.  






uncle harry said:


> Exxair (brand/Co.) makes venturi-based devices for blow-off uses including air knives and nozzles.



We use the exxair blowoff guns at work and they are great.  I didn't realize they sold seperate nozzles as well, the only reason I recommend airtx.


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## grepper

First, I really appreciate all the input here.

I'm not totally inexperienced with tools and machinery.  I've rebuilt engines, transmissions, that sort of thing, so at least I'm not groping around in a clueless stupor, but I am a noob when it comes to mill operation.  Better late than never, eh?  The Internet is full of people who, for whatever reason, feel it necessary to spew advice even when they have no real idea what they are talking about.  I only pay attention to information derived from expertise and experience; the rest is, to me, mostly just babble with only a sparse smattering of pearls of wisdom. 

I recently retired, so now I have a little time to play.  Time I don't want to waste making stupid, uninformed decisions.  Been there, done that.   I've found the best way is through research, and seeking the advice of "grizzled old mentors"  who actually have experience and expertise who are willing to lend a hand.  It's something I hold in great respect and am deeply appreciative of.  Grizzled is good.  So, thank you!


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## grepper

Uncle Harry- The Airtx vortex tube stuff looks very interesting!  I guess the minimum compressor required is  10 cfm, and I only have a puny little compressor.  That would add at least another $500+  to my little hobby project.  Nonetheless... 

This is a money pit and it won't ever end..., will it?


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## Metal

Hey, sorry to bump an older thread, but can someone link or provide information for the DIY microdrop coolant systems? some googling hasn't seemed to bear fruit.


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## JimDawson

Metal said:


> Hey, sorry to bump an older thread, but can someone link or provide information for the DIY microdrop coolant systems? some googling hasn't seemed to bear fruit.



Here is how I did mine, it also works just fine without the pump by controlling the flow with air pressure.
http://www.hobby-machinist.com/threads/digital-mist-coolant-pump.40405/#post-347743

Here is @terrywerm's No-Fog system
http://www.hobby-machinist.com/threads/no-fog-coolant-mister.19957/


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## Metal

Thanks!

Myself, I was thinking "why don't I just use an airbrush?", lo and behold, the second system is basically a big airbrush with an external paint feed


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