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Metal working - dry / lubricants / coatings / cooling mist

CWret

Ultra Member
Premium Member
I’m looking for some advice on this subject, but first some background info. I work predominately with mild steel or aluminum. My experience, for many years, was on a drill press and I used a squirt of Rapid Tap or just drilled dry. In the fall a MD45 bench top mill (RF45 clone) followed me home from Modern Tool. I’m trying to learn about lubricants as well as speeds & feeds. Please cut me some slack due to my lack of milling experience.
The lubes I’m now using are shown in the photo below. The red can is 30 wt way oil. The blue can is equal parts Rapid Tap/Tap Magic/80W90 gear oil (mix rational: Rapid Tap is very popular; Tap Magic is sooooo very thick and tacky; and I’ve got lots of the gear oil). I use HSS EMs and indexable face mills (general-purpose carbide inserts). The ‘blue can’ oil is applied by toothbrush for cutting steel. Aluminum gets lots of WD40 via spray can or ZEP but I’ve seen Forum references to Relton A9, so thinking I’ll give it a try. Also, I might spring for the Viper’s Venom that @Susquatch likes so much (Little Machine Shop, 32 oz @ 62$US + customs).
I started using a hand-held blow nozzle to clear the chips while cutting dry or with lube. I wanted (needed) a more adjustable and hands-free blow nozzle. The one I got has the ability to add mist to the airflow. Even though my intention was to use it for air only, I’m going to try it with some water-soluble mist lubricant. In the pictures, I was testing it with windshield washer fluid. The percentage of liquid in the mist is very controllable. Amazon kindly sent me a magnetic base with an adjustable arm. It’s designed for an indicator but it works great to position or relocate the air nozzle (see pics).

Here are the mist lubricants I’m considering and I welcome your comments:
First - Walter Coolcut S50 (#53-C025) @ $104 from S. B. Simpson - I like their store & it’s less than 20 minutes away.
Second - TRICO TriCool TC1 @ $93 (Flyer price $83) from KBC. Tied for 2nd (also from KBC) is KoolMist77 @ $97. Note that Coolcut, TriCool & KoolMist have somewhat similar specs.
Fourth - KutSol 1GP (#B1624) @ $53 from Busy Bee. Despite the lower cost, it’s 4th because I couldn’t find much info about KutSol and IMO KBC handles higher quality stuff. No delivery cost since KBC & BB are 45 minutes away. BB is actually closer but people would talk if I visited one without the other. (Amazon offers TrimMist, Fein Slugger, KutWell, AnchorLube, Mobilecut, etc. with a bigger $ range.)
Note1: These lubes are miscible with up to 30 parts water. Note2: Prices are for 1 US gallon. Note3: Thought I’d try mist alone and compare that to Tap Magic and mist together. Note4: Air flow is 2.8 cfm at 80 psi. Note5: Coatings seem complicated/specific and over my pay grade. Note6: I think 100% WD40 will work well in the mister for Al. Note7: If I find a ‘round tuit’ I’ll get carbide inserts for aluminum.

FYI: Cutting stock - On the 10” miter saw I: use a 7” blade to reduce tip speed; cut steel dry; cut aluminum with WD40; and use a blade designed for steel or aluminum. On the band saw I keep the blade damp with chainsaw oil which sticks like glue. I also have: oxy/acet torch; 14” electric chop saw; 12” Stihl gas saw; Hypertherm plasma; and a very old hacksaw lubed with elbow grease. (I’ll try the mist sprayer next time the Stihl is cutting flagstone or steel.)
 

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CWret

Ultra Member
Premium Member
The blue plastic hose and nozzle in top photo was my first one. It was a total POC. $15 from Amazon and not worth 15cents.
Here’s sone more pics
 

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CWret

Ultra Member
Premium Member
Will try a video too
 

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Stellrammer

Well-Known Member
The basics:
HSS steel endmills need cooling most,and lubricating to some extent. Think water soluble coolant.
Do not use automotive oil!
Taps , lubrication, use tapping compound, in aluminum use cutting oil mixed with varsol.
Do not use automotive oil!
Drills, a thin cutting oil or emulsified flood coolant. Vegetable based cutting and tapping pastes are effective but hard to breath in the fumes.
Do not use automotive oils!
Bandsaw, needs lubrication more than cooling, a very thick say 20 to 1 of a good brand of emulsifiable oil.
Do not use automotive cutting oil.!
Way lube is for ways
Carbide either a constant heavy flood of emulsified coolant or nothing other than air to clear the chips.
 

CWret

Ultra Member
Premium Member
Thanks @Stellrammer for those tips.
I’ll not use automotive oil any more. The gear oil mix in the blue can will get dumped.

Aluminum: would one of the cutting lubes i listed above work with varsol or should i get something else? What ratio lube to varsol? How would you suggest applying the lube/varsol mix? Mist?
Yes i only use way oil on the ways.

I don’t have any solid carbide tooling. Would you suggest mist for indexed end mills and face mills (with carbide inserts)?

I’ll not be using any automotive oils for milling lube.
 

Dabbler

ersatz engineer
I've been experimenting for decades on cutting and tapping fluids. Everything I've tried helped a lot versus no lubricant at all.

I agree about staying away from detergent oils, they attract moisture in open air, and promote corrosion.

I usually start with sulfated cutting oil.

Tapping
Steel If I am tapping in any kind of steel, I use Sulfated oil full strength.
Aluminum A-9 most times otherwise I use 1 part Sulfated oil, 3 parts wd-40, and 1 part low odor varsol. Try to always use low odor, as the flash point and vapour pressure are far more preferable than old style varsol.
Brass, I substitute way oil for sulfated oil. Do NOT use any sulfated compound and leave it on brass or bronze.
You get copper and zinc depletion and very weak threads
Cast iron: I use WD40 for tapping in Cast Iron. I break fewer taps that way.


Cutting
Steel
For lathe HSS cutters I use 1 part sulfated, 3 parts WD40 and 1 part varsol, for all drilling and turning operations
For milling I use soluable coolant (the kind that PA sells and recommends 1:50 dilution) but I dilute 1:30 and mix
1:1 with 90% methanol or isopropynol. Resists freezing better, no bacterial growth, and better cooling.
I use a ZEP spray bottle (available at Home Despot)

Aluminum drilling, milling and turning: I use WD40

Bronze, all cutting operations: Dry.
Cast iron: all cutting operations Dry.

For almost all carbide operations I go dry.

------------------------------------------

Stefan Gotteswinter uses 3 lubricants: 1) 90% Isopropynol, 2) Soluble cutting oil at 1/2 the recommended dilution, and 3) commercial cutting oil. You will have to troll his last 5 or 6 videos to extract his protocols.
 

Arbutus

Super User
Premium Member
For working in tough materials such as phosphor bronze and some stainless, I've found Johnson's Baby Oil to be effective. Seems to work as well as kerosene but with a nice smell !
 
For Aluminium A-9, Tap Magic Aluminium, MicroChip (Ionic cooling) Flood Coolant.

Most other material, MicroChip or WD40 spot application.

I have a few others but but rarely used.

I started using Microchip in a spray bottle years ago as it greatly helps in heat removal which is the primary cause of cutting issues.
 

CWret

Ultra Member
Premium Member
Thanks @Dabbler. Nice to benefit from your experience.

Tapping:
Been tapping & drilling with Tap Magic full strength for Steel, Al and cast. I’ll get some A-9 for tapping Al from now on. During the mill DRO install, I broke a couple of taps - I'll switch to WD40 for cast
Steel -Took a bit of digging but www info shows Rapid Tap and Tap Magic are sulfated, not sure why they seem to hide that fact. On the other hand, Viper’s Venom seems ok with being known as highly sulfated. Gonna try some V’sV.

Cutting:
Steel - I see that PA’s PowerFist Cutting Oil is similar (I think?) to Coolcut, TriCool, or KoolMist. Not sure about PA's Cutting Oil but the others are synthetic and nonsulfated. Diluted at 20:1 or 30:1 a gallon jug is nearly a lifetime supply for me so I’ll just spring for the Coolcut. I like your tip to dilute with methanol – a good bug killer (bacteria) and will raise the vapour pressure to improve cooling. I too like the ZEP type sprayer – I’m hoping my mist attachment will be an improvement on that. (FYI: No room for lathe, mill only).
Auminum- WD40 -check

Cast - I was drilling with Tap Magic but I had switched to dry & yes that seems better.
Carbide - you say go dry - so does that apply to indexable mills with carbide inserts?
 

CWret

Ultra Member
Premium Member
Appreciate your input @Arbutus
Baby oil: Simple and normal home products often work well in unexpected places, and yes improved shop orders would be a good thing.
 
You are going to find that as you progress you will switch yo Carbide. Faster cutting, better finish, less flex but it comes with a cost, heat. At this point cooling becomes important.
 

Rauce

Ultra Member
I’ll add that I’ve tried isopropyl and denatured alcohol on aluminum for both milling and turning. It works well and is less messy than WD-40. That’s with carbide, not sure if it’s the best choice for HSS and aluminum.
 

Stellrammer

Well-Known Member
I have lots of friends with machine shops, I beg way lube, water soluble coolant tapping compounds from them. A lot of shops won’t mind handing over a litre of emulsifiable coolant if you have a container, then you can make up your own water to oil ratios.
Oddly very few shops seem to have Acculube vegetable based oils or pastes, that you may have to buy.
Thanks @Dabbler. Nice to benefit from your experience.

Tapping:
Been tapping & drilling with Tap Magic full strength for Steel, Al and cast. I’ll get some A-9 for tapping Al from now on. During the mill DRO install, I broke a couple of taps - I'll switch to WD40 for cast
Steel -Took a bit of digging but www info shows Rapid Tap and Tap Magic are sulfated, not sure why they seem to hide that fact. On the other hand, Viper’s Venom seems ok with being known as highly sulfated. Gonna try some V’sV.

Cutting:
Steel - I see that PA’s PowerFist Cutting Oil is similar (I think?) to Coolcut, TriCool, or KoolMist. Not sure about PA's Cutting Oil but the others are synthetic and nonsulfated. Diluted at 20:1 or 30:1 a gallon jug is nearly a lifetime supply for me so I’ll just spring for the Coolcut. I like your tip to dilute with methanol – a good bug killer (bacteria) and will raise the vapour pressure to improve cooling. I too like the ZEP type sprayer – I’m hoping my mist attachment will be an improvement on that. (FYI: No room for lathe, mill only).
Auminum- WD40 -check

Cast - I was drilling with Tap Magic but I had switched to dry & yes that seems better.
Carbide - you say go dry - so does that apply to indexable mills with carbide inserts?
Carbide - you say go dry - so does that apply to indexable mills with carbide inserts?
If you can contain flood coolant by all means use it on indexable. If you can’t dry is okay, you probably won’t be pushing the envelope on speed and feed.
Heat resistant alloys benefit from coolant and it should be used ,generously.
The reason I say flood well or not at all is due to thermal shock, the insert heating up in cut and then being exposed to shock of cold coolant hitting it on the way out of the cut. A heavy and directed stream of coolant can regulate the temp , a little bit , not so much.
Squirting a stream of coolant from a bottle onto hot carbide is asking for trouble. There are thermal shock resistant grades of carbide available but your choice of insert should not hinge on that parameter.
I’m mostly going dry with air nozzle, I seldom use HSS but have a lot of different sizes on hand for the occasional need for length or size. Solid carbide is my first choice for everyday use, I really don’t like inhaling emulsified oils or any cutting oil vapor, misting, not for me.
There are plenty of excellent tapping compounds out there , some way overpriced but they all are effective compared to dry.
 

Dabbler

ersatz engineer
With stainless you’d want to use coolant more often with carbide.
You should take a deeper cut in stainless, increasing your heating load, and the need for coolant. This is true for HSS as well.
I’ll add that I’ve tried isopropyl and denatured alcohol on aluminum for both milling and turning. It works well and is less messy than WD-40. That’s with carbide, not sure if it’s the best choice for HSS and aluminum.
Thanks, I was going to test that, now I'll use that instead.
Squirting a stream of coolant from a bottle onto hot carbide is asking for trouble.
absolutely.
 

CWret

Ultra Member
Premium Member
@Rauce, @Degen, @Stellrammer, @Dabbler

Rauce - You said “isopropyl or denatured alcohol on Al with carbide is less messy than WD40” That makes sense since it will evaporate quickly. But that is a flammable liquid mixed with hot chips and also a lot more stinky than WD40. Are the fumes & fire risk worth it? Dabbler mentioned that he also uses isopropyl (or methanol) but in a mist & diluted with water so I guess not nearly as risky?
Where do you source the isopropyl (or equivalent)? It’s expensive in small bottles at the drugstore, I don’t think Home Depot has it, and Amazon charges as much for delivery as for the product.

Degen said – “you’ll switch to carbide and then cooling becomes important”
FYI - This morning I ordered some solid carbide EMs from AliExp (4,6,8,10,12 & 18mm dia). So, as I just asked Rauce above, what cooling method for a carbide beginner?
Logic would tell me that a solid carbide EM would have inherently better cooling due to the solid mass compared to a 2-component indexable EM. So do I cool a solid carbide EM differently that a similar-size indexed EM? And what about my 3” indexed face mill?


Stellrammer and Dabbler responses pretty much answered a lot of my remaining questions.
But for clarity:
I don’t want (or am I set up for) flood coolant. I work primarily with mild steel or aluminum but on rare occasions stainless steel. As a retired guy who’s using caution while learning machining, I’m NOT wanting to jump into the deep end to push any envelopes on speeds or feeds. (FYI: This does not mean that I’m timid - I was an explosives specialist and for 40+ years my hobby was racing motorcycles.) If dry is OK for indexable and solid carbide, then I’m OK with dry. The potential for damaging thermal shock from inconsistent coolant contact makes perfect sense. Thanks for emphasizing that. Dry + an air nozzle - good advice! I too am not enthusiastic about inhaling nasty fumes from sulfated or emulsified oils (this reinforces my concern about not using big amounts of isopropyl).

More clarification please: If flood coolant or dry is best for carbide in steel, OK then, but would a consistent mist sprayed directly at the carbide cutter still result in thermal shock? Stellrammer said, “A heavy and directed stream of coolant can regulate the temp , a little bit, not so much.” So, is the mist a help or a hindrance?

Back to using my HSS EMs in mild steel, which is the best choice: sticky sulfur lube applied by toothbrush; mist of miscible synthetic biodegradable lube; or dry + air from a nozzle.

I don’t do a lot of tapping. Therefore, a top-shelf thick lube (Tap Magic) is what I plan to continue using. Not a lot of fumes or expense involved. I use the same products for drilling for similar reasoning.


FYI: In my post #3 picture above, I was comparing drilling with titanium-coated bits vs 5% cobalt bits vs 5% cobalt annular cutters. One hole dry & then a hole using the same bit but with Tap Magic. I did this a couple of weeks ago after just receiving my first set of annular cutters and also a new set of cobalt drill bits. Verdict (with lube): it was 10 to 15% faster; had similar hole quality; and fewer blue hot chips at breakthrough. Not enough drilling to comment on wear, but fewer blue chips would imply longer life using the lube. The material drilled was in 5/8” mild steel and also 3/8” SS. (Another verdict: annular cutters are awesome; and I can’t believe it took me this long to learn that.
 

Dabbler

ersatz engineer
Dabbler mentioned that he also uses isopropyl (or methanol) but in a mist & diluted with water so I guess not nearly as risky?
I never use mist. The closest I get to mist is a Zep squirt bottle. To each....
If dry is OK for indexable and solid carbide
Running carbide dry will wear out carbide quicker, but the alternative is to keep it very wet with soluable coolant.
5% cobalt annular cutters
Personally I use soluable coolant with isopropyl on annular cutters. I keep it completely covered. It is very cheap per hole - and I cut a LOT of holes, so that's why I go soluable oil/iso.... My chips never are coloured when I do this, so I must be getting very good cooling.

I don’t do a lot of tapping.
I can recommend Anchor Lube, then. I think it is expensive, but if your 12$ bottle lasts for 10 years, why not? It does work very well in almost any material.

I got a gallon of 97% isopropyl somewhere about 10 years ago, and I still have some. But I cannot remember where I got it. I paid about 40$ for it then. I'd like to get a gallon of methanol in above 90% grade, so shopping trip soon!
 
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