# Lathe Coolant system or Cutting Fluid,  What do I need



## Investigator

I don't know what I need, if anything.  I have read about flood coolant systems for lathes, and I know there is a difference between coolant and cutting fluid.  My question is do I need some type of coolant system?  IF so what kind?  What about cutting fluid, so far I'm dripping it onto the work from an oil can.

My lathe is a 12" Logan.  I have been working with aluminum using WD-40 as cutting fluid, and I have been using 17-4 Stainless (which cuts much better than anything else I've used) and using 30w oil on it.  I have tried cold-rolled steel with the 30w also.

So please tell me the pros and cons of using coolant and cutting fluids.  I don't even know how much I don't know.

Scott


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## Bob Korves

Flood coolant makes a mess, otherwise is the best.  The water based coolants also need to be taken care of, they get bacteria growing in them and stink badly.  Definitely requires maintenance.  Flood type coolants can also be squirted on from a squeeze handle plastic bottle manually, or from a air powered mister unit.  Some people flood cool using cutting oil in the system.  Can be a huge mess, and oil does not hold as much heat as water does.   A simple air blast stream on the tool and work can also help cool the job.

Coolant is needed for maximum cutting performance, speed, and metal removal quantity.    Many or most hobby machinists will just use cutting oil to improve the surface finish and slow the process down enough to keep the heat down to an acceptable level.  We are not getting paid by the piece.  I would suggest to try using an acid brush for applying the oil to the part, perhaps easier to get the oil where you need it.


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## Investigator

Bob Korves said:


> Flood coolant makes a mess, otherwise is the best.  The water based coolants also need to be taken care of, they get bacteria growing in them and stink badly.  Definitely requires maintenance.  Flood type coolants can also be squirted on from a squeeze handle plastic bottle manually, or from a air powered mister unit.  Some people flood cool using cutting oil in the system.  Can be a huge mess, and oil does not hold as much heat as water does.   A simple air blast stream on the tool and work can also help cool the job.
> 
> Coolant is needed for maximum cutting performance, speed, and metal removal quantity.    Many or most hobby machinists will just use cutting oil to improve the surface finish and slow the process down enough to keep the heat down to an acceptable level.  We are not getting paid by the piece.  I would suggest to try using an acid brush for applying the oil to the part, perhaps easier to get the oil where you need it.



I assume by flood coolant we are talking about water soluble solutions?  What effect does this have on the machine? Any rusting issues?


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## Ken from ontario

I recently decided to try one of those cheaper misters we often see on ebay/amazon so I ordered one and also the water soluble coolant for it, have not received my order yet but I'm thinking even if the mister does not work as it is supposed to or if it makes a huge mess, I could still use it as a blower to cool the workpiece down and blow the chips and the smoke away away so for the amount of money involved, I think it's worth a try.

I can manage with cutting oil when machining Aluminum but I get  a lot smoke when cutting steel, and the level of smoke gets so dense that I have had to stop 3-4 times  and open the front/back doors to let the smoke out so I can breathe,  I do dread the thought of machining steel for that reason.


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## Jimsehr

For production flood. For home shop I use a small air brush that I bought from Harbor Fright for 10 bucks. Works good when drilling deeper holes. Only holds a small amount of coolant . It has a small glass jar.


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## Ray C

If you do machine work on a regular basis and do not have good ventilation, using oil will eventually lead to health problems.   I didn't think it would happen to me but, it did -and I don't smoke cigarettes or cigars either. 

Flood vs Mist.   This reminds me of the age-old battle between Wedge or Piston tool-post systems or, oil-change intervals for your car or, what brand of oil filter is best.   Pick one and stick with it.   Be mindful that if you are new to machine-work, don't expect a coolant system to solve all your problems and give you a mirror finish on everything you touch.

That said, I personally used to use just oil.  After 5 years of that out in my garage, I developed bronchitis and was bordering on COPD.   I used flood coolant for a couple years and found it to be messy and a lot of work -and it often didn't cool the part down very much at all.   About 8 years ago, I switched to a mist-type system and never looked back.  Like anything else, it has a few tricks to use properly.  

Please check this thread starting at post #20.   http://hobby-machinist.com/threads/for-those-who-think-all-pm-owners-keep-pristine-equipment.63921/

Parting shot is:  Save your lungs and totally minimize using any kind of oil.  I only use it for tapping and thread cutting now.


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## mikey

I've been experimenting with Anchor lube because of the smoking issue with cutting oils. So far,  it seems to work pretty well for most things I turn and no smoking issues. Anything that aerosolizes a fluid gets into the air so no coolant or mister systems for me.


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## Ray C

Oh, forgot to mention about the difference between coolant and cutting fluid.  For the purposes of most lathe, mill and grinding work on most kinds of common metals, the two things are different animals.   Coolant's cool things and have additives to keep algae down, keep rust under-control and not dissolve lubricants (such as way oil) too badly.   Cutting fluids are often sulfur-based but can be other forms of fairly strong chemicals.  They make no attempt to prevent algae or otherwise be nice to you or your machinery.    Cutting fluids are typically used for high pressure, slow-speed operations.   There are some fairly complicated interactions at the level of molecules when metal is torn away by carbide or cut by sharp HSS but in either case, by adjusting the tool bit position, the type of tool bit (carbide or HSS) or the speed/feed, you don't need cutting fluids for standard lathe, mill or grinding operations.   Lubricants (which are different than cutting fluids) on the other hand, can help with general machining but, the down-side is the smoke -which will eventually cause lung issues.   In my case, I'm OK with using mist-type solutions because, the main ingredients are also used in various food-processing additives.  They all have an MSDS Health rating of 1 (on a scale of 0-4).  Most motor oils and the ingredients therein have an MSDS health rating of 2 or 3.

Regards

Ray C.


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## Investigator

Ray C said:


> If you do machine work on a regular basis and do not have good ventilation, using oil will eventually lead to health problems.   I didn't think it would happen to me but, it did -and I don't smoke cigarettes or cigars either.
> 
> Flood vs Mist.   This reminds me of the age-old battle between Wedge or Piston tool-post systems or, oil-change intervals for your car or, what brand of oil filter is best.   Pick one and stick with it.   Be mindful that if you are new to machine-work, don't expect a coolant system to solve all your problems and give you a mirror finish on everything you touch.
> 
> That said, I personally used to use just oil.  After 5 years of that out in my garage, I developed bronchitis and was bordering on COPD.   I used flood coolant for a couple years and found it to be messy and a lot of work -and it often didn't cool the part down very much at all.   About 8 years ago, I switched to a mist-type system and never looked back.  Like anything else, it has a few tricks to use properly.
> 
> Please check this thread starting at post #20.   http://hobby-machinist.com/threads/for-those-who-think-all-pm-owners-keep-pristine-equipment.63921/
> 
> Parting shot is:  Save your lungs and totally minimize using any kind of oil.  I only use it for tapping and thread cutting now.



Just to understand better.....

On the cooling mist system, does it have it's own air pump or is it hooked up to a regular air compressor in the shop which also has to run?


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## Ray C

Investigator said:


> Just to understand better.....
> 
> On the cooling mist system, does it have it's own air pump or is it hooked up to a regular air compressor in the shop which also has to run?



They come in all kinds of configurations.  Most of the systems run off typical shop compressed air.   If you look at that thread I referred you to, I showed some links to misters that cost about 10 bucks.  I run mine at 40-50 PSI and the air-flow is so low, I'd say I have leaks in other fittings in the system that waste more air than my mister does.   FWIW, I use Kool-Mist branded solution.  Comes in 8 oz bottles.  Mix 1 cap to a quart of water.   A quart last me several days to a week of heavy lathe use.

These are my personal thoughts/opinions/practices.  Your mileage may vary and I highly encourage you to experiment.   Like I said, the only thing I really encourage is that you stop using oil lest you damage your health.

Regards

Ray C.


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## Investigator

Ray C said:


> They come in all kinds of configurations.  Most of the systems run off typical shop compressed air.   If you look at that thread I referred you to, I showed some links to misters that cost about 10 bucks.  I run mine at 40-50 PSI and the air-flow is so low, I'd say I have leaks in other fittings in the system that waste more air than my mister does.   FWIW, I use Kool-Mist branded solution.  Comes in 8 oz bottles.  Mix 1 cap to a quart of water.   A quart last me several days to a week of heavy lathe use.
> 
> These are my personal thoughts/opinions/practices.  Your mileage may vary and I highly encourage you to experiment.   Like I said, the only thing I really encourage is that you stop using oil lest you damage your health.
> 
> Regards
> 
> Ray C.



Any limitations on what material you can use the coolant on?  I have seen some soluble mixes that are meant for specific materials, or some have said not for titanium.  Just wondering if it will work on everything, or if you have to have other formulas if you change materials.


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## Tozguy

Ray just wondering where the coolant drains to (if at all) and do you reuse it?


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## Ray C

@Investigator:   I use the Kool-Mist 77 solution on everything.   At one time, I did try the stainless-steel specific stuff but honestly saw no difference.   I also ran out and just used water for a couple days and that worked fine too.  -Not recommended though.

@Tozguy:  It's not reused and no drains are needed.  My lathe sits in a tray and I have a cookie sheet underneath the front part near the chuck.  Once you find-out how low you can set this to for your given application, you will probably only use about 1-2 ounces of working fluid in an hour of cutting.  Sometimes I use those blue bed-sheet absorbent pads (used in hospitals for people prone to pissing themselves) on the front part of the ways if I'm doing extended work.  Been using the same one for about 3 months now.  You gotta be careful that it does not get snagged by spinning swarf and slap you in the face.  I use little magnets to hold it down.

Regards

Ray C.


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## Ray C

Regarding the Kool-Mist solution.  Here's the summary from, and a link to the MSDS.  https://archive.org/stream/KoolMist77MSDS2013/Kool Mist Formula 77_djvu.txt


Ray

Non-hazardous when ingested. May cause mild irritation to the gastro-intestinal (Gl) tract if 
excessive quantities are ingested. 

Excessive inhalation of product mist may cause mild irritation. 

Essentially non-irritating to the skin. Prolonged exposure to undiluted product may cause mild 
irritation and dryness. 

Mist may cause mild eye irritation in sensitive individuals. 

In sensitive individuals certain medical conditions may be aggravated by prolonged exposure, 
including dry skin and/or dermatitis, and pre-existing chronic upper respiratory diseases such as 
bronchitis, emphysema and asthma.


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## ttabbal

This is interesting. I was originally planning to use the normal cutting oils on my lathe, but this has me thinking I should consider trying the mist setup and reserve the oil for tapping and such. I understand how the evaporative and flood cooling would work, does the solution contain something to help ease the cutting forces like oils do? The marketing claims it does that and has rust prevention additives. I'm wondering how it compares to other users here though. 

I like the idea of avoiding unnecessary exposure to chemicals. I was planning to just increase ventilation when running the lathe, and will anyway to some degree, but not getting more stuff into the air is even better.


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## Downwindtracker2

Industrial Dermatitis , I know two tradesmen that had to give up their trades. One a machinist, the other a millwright/heavy duty mechanic. It was tough to see his hands cracked and bleeding. That's oil for you. 

It's been 30 years since my pre-app days, we studied this, but some water soluble ones do have lubricating properties. For the lathe I have a Little Giant pump, a square pail and mag-base nozzle, my even use it.

I don't have dust extraction system for my little Delta Toolmaker, so I'll be putting a mister on it.


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## Ray C

ttabbal said:


> This is interesting. I was originally planning to use the normal cutting oils on my lathe, but this has me thinking I should consider trying the mist setup and reserve the oil for tapping and such. I understand how the evaporative and flood cooling would work, does the solution contain something to help ease the cutting forces like oils do? The marketing claims it does that and has rust prevention additives. I'm wondering how it compares to other users here though.
> 
> I like the idea of avoiding unnecessary exposure to chemicals. I was planning to just increase ventilation when running the lathe, and will anyway to some degree, but not getting more stuff into the air is even better.



Once again, there's a difference between oils/lubricants and cutting fluids.  Oils do not reduce cutting forces.  Only cutting fluids do.  When it comes to oil/lubricant, the only kind that serves as a cutting fluid is high-sulfur cutting oil or what's called bar & chain oil.   Lubricating oil and hydraulic specifically have as much sulfur removed from them as possible.   If you regularly use cutting oil and get it on your ways, the sulfur will eventually make dark stains that cannot be removed w/o very abrasive sanding.

Oils and lubricants can be helpful when cutting on a lathe but not because it's acting as a cutting agent but, because, it's acting as a friction reducer which prevents the junctions from chattering.  You could use water or spit if you wanted to.

When you mix flood coolants it's usually something like 8 oz's of stock solution to a gallon of water.  Kool-mist is something like 32 or 48: 1  (1oz stock solution and 31 or 47oz of water).   When you feel it, it feels just like water.  It's not slippery at all.  The ingredients are mainly there to act as algae and rust inhibitors.  The other main ingredient (Triethanolamine) is used in sun-screen, hand lotion and is an emulsifier so it will get along with your way's lubricating oil.

Hope that helps...

Ray C.


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## Investigator

I think there was a mist tank setup in the stuff I got with the lathe.  I'll check and see.


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## menace

I've had a coolmist77 set up on my milling machine for many years with no problems. I piped air to it though an old hospital regulator and keep the psi low, less than 10 psi to keep too much mist from forming. It lasts a long time! I put a blue paper shop towel in line of the mist to absorb excess. The chips are cool and are pushed away from the cut but don't fly away to far with the low pressure, cleanup is easy. I haven't had any rust problems either! My 2 cents, Steve.


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## Investigator

Look what I found with the 'extra stuff" that came with the lathe:



Looks like a decision has been made for me.


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## Ray C

Investigator said:


> Look what I found with the 'extra stuff" that came with the lathe
> 
> Looks like a decision has been made for me.



Well, alrightee then...  you're set.   If you place the supply container high-up at about the same level as the discharge tube, you'll be able to run it on very low air pressure.

Have fun...

Ray C.


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## Investigator

And the question now becomes which coolant to use? The cool mist brand or any others? Right now I have plans on working with 17-4 stainless as well as some 4140 Steel. And of course aluminum every once in awhile


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## outsider347

Subscribed..

I have been thinking about removing the flood system from my new PM 1236.  Really don't want the the  mess & maintenance issues
Tks Ray C


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## Bob Korves

Your mister will work great.  You may need to work at getting old gummed up coolant cleaned out of it.  Rinse the unit and the piping after each use for best results long term if it will dry out between uses.  For coolant, try this:
http://koolmist.com/formula-77-for-tougher-service
When using it, you only need a small amount of air and coolant to do the job.  No big puddles should be created.  Cleanup should be able to be done with a couple paper towels when finished.  If you end up with a mess, you are using too much coolant.


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## Ray C

Investigator said:


> And the question now becomes which coolant to use? The cool mist brand or any others? Right now I have plans on working with 17-4 stainless as well as some 4140 Steel. And of course aluminum every once in awhile



As mentioned, I only use the #77 fluid and I've used it on everything from mild to high carbon steel and many of the 41xx alloys in both fully annealed and hardened up to the RC 45-50 range.  Also have used it on the common 300 series stainless with no problem.   Have not cut any 17-4 but, it's my understanding it is similar to the 300 series stainless.   If you're new to machining, learning the basics of machine operation with aluminum and/or mild steel might be a less frustrating route.   Stainless is really tough stuff and will play games with newby operators ...  

61xx series aluminum is good to learn the basics.  1030 to 1045 steel in the normal condition is also good to learn on.   A36, 1018 and 1020 are easy to cut but a little unpredictable (kinda gummy) to get a smooth/beautiful finish (which every lathe operator loves to see).

Regards

Ray C.


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## dennys502

I use Trim Microsol 585xt for my flood coolant.
 I use flood for everything I do. It does get expensive as it evaporates rather quickly.


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## Bob Korves

mikey said:


> I've been experimenting with Anchor lube because of the smoking issue with cutting oils. So far,  it seems to work pretty well for most things I turn and no smoking issues. Anything that aerosolizes a fluid gets into the air so no coolant or mister systems for me.


Anchor lube is a good choice.  It comes as a thick paste, and works on just about anything, from aluminum to stainless.  It is water based, and can be diluted to whatever consistency you want for what you are doing.  It clings to taps and drills so most of it gets into the cut, if you thin it and use it correctly.  It is non toxic, and smells good, too!  I have quite a bit on hand, but for some unknown reason rarely use it.  Strange, because it works very well.


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## middle.road

I moved the Lil' Mister from the mill over to 1440, and ordered one of the $10 blue and orange misters off of eBay for the mill.
It goes through much more liquid that the Lil' Mister though. I'm still using Boelube @20:1 and do have problems with rust, but I think I may have figured out a partial solution for that.
What the wiping up doesn't get I've been spraying the area down with WD-40. Still had a mess under the mill vise.

Then I was working with lucite on the lathe and the only thing I could get to work for a decent finish was water with a dash of soap.
Using a windshield-washer pump, I jerry-rigged a nozzle off a nasal spray bottle and hooked up a foot switch.
And then had to put shielding on all over to keep the water at bay. Amazingly it is still functioning.
Quite a bit quieter than running the compressor for a mister. (gotta move the compressor someday... else find a quiet one.  )


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## Tozguy

Ray C said:


> Well, alrightee then...  you're set.   If you place the supply container high-up at about the same level as the discharge tube, you'll be able to run it on very low air pressure.
> 
> Have fun...
> 
> Ray C.



Makes me wonder if we could not just raise the supply bottle higher and have a gravity feed without any air or mist at all. Just have a wick resting on the work ahead of the cut with a slow drip keeping the wick wet ????


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## Eddyde

Tozguy said:


> Makes me wonder if we could not just raise the supply bottle higher and have a gravity feed without any air or mist at all. Just have a wick resting on the work ahead of the cut with a slow drip keeping the wick wet ????



That may work if you just wanted to apply some lubrication to the surface of the work. The mist system gets coolant/lube to the entire cutting area, it can be positioned to spray at an upward angle to get the fluid directly to the tip of the cutting tool. Also, the venturi effect adds additional cooling as the compressed air is expanding. 
I have a Kool Mist unit, right now, I move it from machine to machine as needed, eventually, I will get dedicated ones for each machine. I think it's the way to go for hobby or non production shops.


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## Wreck™Wreck

It depends on the material and operation.

I single pionted threads in 110 copper parts today, (electric switch contacts) tried general purpose water soluble coolant, this did not work.

Then cutting oil which worked better yet not ideal.

The last resort that I knew would work was lard oil, we do a lot of copper work so always have a 5 gallon pail of it around, and as usual it worked a charm. However I loathe using it but had no choice.
Turned some parts last week in free machining  tellurium copper alloy which machines nearly as easily as 360 brass, if you need to make conductor components from copper, it is an excellent material for this purpose.


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## BGHansen

I use Kool Mist 77 on my mill or straight shop air.  Use TrimSol for the flood coolant on my lathe, and it doesn't get used very often.  As mentioned above, it makes a big mess, especially if it hits the chuck.  I don't have issues with rust but wipe down the lathe and spray it with LPS 1 lubricant after every use.  The LPS 1 displaces the coolant really well.

Bruce


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