51 Papy

Drill bit lubricant

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Santa brought me my first set of "good" drill bits.  They are Drill Hog M-7 bits.  I have always bought big box- hardware store quality drill bits and used old motor oil as a lubricant.  With my limited Google Foo I am now wondering what I should be using.  There are websites that swear by motor oil, WD-40, Paste, gel and one website said diesel. I'd like to make these last as long as possible.  Anybody have any favorites?  I don't drill much harden material mainly mild or annealed.  Or, am I overthinking this?

 

Thanks

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Mr. 51,  Papy,

May I suggest that you,  also,  have a look at high sulfur cutting oil.  Especially when drilling hardened steel at low r.p.m. 

A small amount of same,  will last you many years

Just sayyin',

SLAG.

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My choice varies from the heavy cutting oils to water based fluid.  Because I have it around for my machine shop, I often prefer to mix a strong level of water based cutting fluid and put it in a squirt bottle.  The benefit of that stuff is easy clean-up...and it doesn't smoke under heat of drilling which can be an issue at times.

 

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Merry Christmas,

"Oil" is a lubricant, it resists the ability to 'Cut'. Water is the best for cooling a cutter or cutting face, but water can cause rusting. Like what is already said above, use a water base cutting fluid. Drill slow enough to get your job done, not so fast as to burn the cutting edge.

The angle of the cutting face is different for steels, brass, aluminum. Keep a different set of drill bits for the softer material.

When drilling out a broken steel stud in aluminum "NEVER USE AN EZE-OUT"!!!!! The Eze-out will expand and make the stud tighter, in the aluminum. I always drill a small pilot hole as close to center as you can, then drill one size smaller than the tap drill size (this allows you a little wiggle room, to push the drill so it is on center). When you start your tap, you will break out the outer edges of the broken bolt/stud and be left with the original thread (original size).

Neil

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16 hours ago, 51 Papy said:

and used old motor oil as a lubricant.

I like everything suggested in response, so far, to 51 Papy's initial question.

My least favorite cutting lubricant would be WD-40. Do not employ used motor oil, as it has diminished viscosity and is likely abrasive, which will promote premature failure of the margins, which can not be reground.

It is amazing how many different materials can be successfully deployed in metal removal - I use Pam for machining (turning, drilling, milling) aluminum (short run and prototyping - helps keep my lathe clean) Boelube Paste for machine tapping, reaming, and milling in aluminum and steel, viscous oil for large diameter shallow drilling. Water soluble oil coolants (mostly water) are well loved by those who understand their application. the other day, I had to use my Portaband to cut 8" from four separate posts of some commercial pallet racking. Last years festive candle did the trick a treat. Paraffin is well suited for high-tooth-count cutting.

The bugaboo for most cutting operations is when insufficient "rotation, or exchange" of heated coolant is maintained, resulting in boiling, or if hotter, a Leidenfrost barrier is generated, and "hotter", ignition. Special circumstances required for the ignition of water, eh? 

Mr. swedefiddle, I am not understanding this statement: "Oil" is a lubricant, it resists the ability to 'Cut'. Would you elaborate? I will put off my initial response to your statement, as I often miss an obvious point.

51 Papy, may your new loot bring you great pleasure and productivity,

Robert Taylor

 

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Why do you put motor oil in the engine of your vehicle? So the parts are "lubricated" and DO NOT cut into each other. Then why would you use motor oil when drilling metal when you actually want the drill to cut into the metal?

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Most cutting enhancers I have used are lubricants, a bit of candlewax on the hacksaw, lard for tapping, etc we had a bit of a  discussion about this a decade ago here...

 

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Thanks guys!  This gives me a place to start.  I picked up some high sulfur dark cutting fluid today and ordered a bottle of tap magic.  If someone has a favorite water borne lube I'm all ears.  

 

Glenn.     Stupidity.... It's what I've seen used in shops.... I'm not sure I have a reason.  It is better than nothing but your point is taken. Thanks

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Interesting set of replies. However they seem to show some misconceptions.

Cutting lubricant is not an oxymoron but it does sound like it. Lubricant is to reduce friction and a cutter, be it a milling bit or a drilling bit or a lathe tool needs to cut. 

A cutting tool has a sharp edge, or several, and a body that is designed to keep the cutting edge steady and channel the chips away from the cut ... generally speaking. 

Cutting generates heat, and the non cutting parts of the cutting tool body rub without cutting on the material generating even more heat. There are two obvious ways to dissipate this unwanted heat. 

Lubricating the cutting tool will diminish the heat generated from friction whilst the cutting is only marginally affected since the high pressure of the sharp edge will displace any lubricant and keep on cutting.  

Refrigerating the cutting tool is another way to make cutting metal a long term proposition, ergo the invention of emulsions of oil and water. Water will cool due to it's high specific heat that will take the heat away from the business end and the bit of oil aid with the friction. 

The shape and angle of the cutting tool, and the material to be cut, determines the lubricant that is more adequate. The lubricant for an automatic milling machine cutting brass gears for example is a mixture of oil diluted with kero. if you are drilling Stainless, cooling is your main concern. 

So there is no one answer and the best is the one that works for you and what you are drilling or shaping ... but in general terms, to cut or drill you need ... a lubricant. :)

Best way to visualise the need for lubrication in a cut is when you try to cut rubber with a knife. Do it dry and struggle. Use water as a lubricant and cut like butter. 

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4 hours ago, Glenn said:

why would you use motor oil when drilling metal when you actually want the drill to cut into the metal?

Components in an engine are meant to slide past one another. In metal removal, the angle of attack different. Only the cutting edge is meant to sever the work - the rest of the tool is meant to slide cooly past the waste being ejected from the cut. Heat goes into the chip because it is being plasticly deformed, whilst Tool geometry and lubricity isolates the cutting tool from that heat.

Marc1, I find your presentation to be clear and succinct.

4 hours ago, ThomasPowers said:

we had a bit of a  discussion about this a decade ago here... 

Thanks for that link, Thomas.

Robert Taylor

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Oils also help keep certain alloys from galling or getting stuck onto the cutter. The CNC screw machines at my last job used a mineral oil based cutting fluid, and they would run spindle speeds upwards of 12,000 RPM.

Water and baking soda will work and doesn't rust things up.

I loved using the 1,1,1, Trichlor I had access to, but my supply is gone now.

I have used some chlorinated carb cleaners to great effect for drilling and tapping.

 

 

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It sounds like the easy answer to my question is  there is no easy answer.  This discussion,Thomas's discussion from 10 years ago and PM's have been very educational.  I'll have a couple by next week and water and baking soda sounds like it's worth a try as long as I don't get caught getting the soda.  Thanks for the guidance!

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The real answer is actually pretty easy, it's knowing what cutting lube is for. It's NOT a lubricant it's a coolant. Too thick an oil can cause chips to jam in the flutes, gall and break the bit so do NOT use thick oil! GREASE! :o Blankety BLANK NO!

Water works fine but you need enough of a flow to keep chips flushed out of the hole. The benefit of it cooling so well is it makes cuttings brittle so they snap clear. However a nice one piece curl of a cutting is better as it clears the flutes cleanly and can't jam and gall. 

Water soluble oils are good, you can adjust the dilution to suit the job. I like it thick enough for a little slippery but not so much it makes a serious mess.

The old school sulfured cutting oils work well, have for well more than a century, it just smells. 

The real trick to drill bit longevity is to keep them SHARP and learn the proper bit speed and how much down pressure to apply. You want those two curls coming out of the hole and that soft crunchy sound, they're saying I'm a happy drill bit. Don't forget to break the cuttings regularly. :)

Breaking the cuttings means stop feeding the bit till the curls snap off then retract the bit clear of the hole sweep the cutting clear (USING THE CHIP RAKE!!!) before putting a couple drops of oil in the hole and returning to work. Add a couple drops now and then while you're drilling you don't want the cutting faces to dry out and get hot. 

Heat is the enemy of metal cutters be they mill cutters or hack saws. Heat runs the temper so they're no longer hard enough to cut, then the edges roll and you're just burnishing. No amount of oil or hanging from the drill press handle will make a drill bit sharp again. I don't care what you see on Forged in Fire! Some of those guys have pretty poor shop skills, might make nice knives but don't know diddly about a metal shop.

Frosty The Lucky.

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Thanks Frosty.  I cheat on my drill bits.  Several years ago I picked up a Foley Belsaw.  I sharpen everything from planer blades to sissors with that thing.  There's a special hard stone and holder for drill bits.  I've gotten plent of experience with bits from HD.

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4 hours ago, Frosty said:

The real answer is actually pretty easy, it's knowing what cutting lube is for. It's NOT a lubricant it's a coolant. Too thick an oil can cause chips to jam in the flutes, gall and break the bit so do NOT use thick oil! GREASE! :o Blankety BLANK NO!

 

Hum ... at risk of being contentious Frosty, the answer is not easy. It may sound easy if you read the multiplicity of answers from people who have been drilling steel for decades, and each having a different answer and swearing that each one work the best, from candle wax to water. 

Cutting fluids can be classified in 4 kinds, Mineral oil, Soluble oils, Synthetic oils and Semi Synthetic oils according to Houghton International. I use their Synthetic oil for my Cold cutting saw and for the broche cutters hole saw and twist drill bits. The reason I chose synthetic oil is that it does not decompose and my intermittent use of the machines will not mean flushing the sump and clean out bacterial growth every month. Also ... Synthetic oil has a better cooling property then mineral oil. 

Cutting fluids have a few different purposes, one of them clearly cooling, but that does not mean they do not act as a lubricant. If all it is required from the cutting fluid is cooling, the same result could be achieved with a hose delivering compressed air directly to the cutting tool. The drill would not last long even cool for ... well, lack of lubrication. 

Of course one can improvise and use different lubricants, motor oil for once works OK, if mixed with a bit of kero even better. Candle wax works good for cast iron, and water works for a little while for your bandsaw providing you cut just little bits here and there. Do some real work and destroy your bandsaw or circular saw with just water. 

The viscosity of your cutting fluid is a product of the material to cut or drill and the geometry of the cutting tool. Cutting lubricants can be paste or solid, to very fluid like kero or diesel, and everything in between. 

There is a mountain of information on the types and purposes of cutting fluids on the web, from the commercial suppliers to the YouTube tips and tricks. Cutting tools need to stay cool and lubricated to keep their edge and integrity for longer. Yes, Cutting Oil is a coolant and a lubricant at the same time.

Cutting tools are in general very forgiving if you use them within the parameters they are made for, meaning ... speed, feeding rate (or pressure) ... yes, the monkey hanging from the pedestal drill handle comes to mind Frosty, ha ha ... and material to be cut or bored. if you care for your drill bits or some very expensive broche cutters, you are well advised to use a proprietary synthetic oil (my choice) Will light motor oil work too? Sure, for a while, and may be for a long while depending on use. Synthetic cutting oil is cheap. I bought 5L a year ago I believe for $40 or so. Mix is 10:1 with water. I am down to the last litre.  Not a big expense, when you compare with the cost of cutting tools. 

 

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Happy almost,

This sounds like this topic has grown out of proportion. Really, it is not a problem to use anything. Old Machinist Handbooks recommended Water with a bit of (sulfer?) to diminish the rust factor (for mild steels). I quite often don't bother with any coolant, just adjust your drill speed accordingly. It is easier to clean up a water base coolant.

Cutting fluid for Aluminum is Kerosene, most penetrating oils are Kerosene base. Cutting a thread in aluminum makes a cleaner job when using a penetrating fluid.

Papy asked a question, I believe his question has been answered.

Neil

 

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Oh my Marc, you sound like a salesman! If we were talking about a production shop then we'd be on the same page, especially CNC operations. It's still much less a lubricant than coolant and in a high production situation and depending on what's being drilled a heavy fluid is used to clear cuttings and is even less a lubricant. 

No: what, when and how to use cutting fluid is simple. The secret is to keep the bit in good condition and use it properly. 

I frankly never use anything when drilling unless it's a special material or situation, I drill salvaged leaf spring as found dry and those bits have stayed sharp for years between sharpening. The real secret to keeping bits, saws, etc, sharp is to NEVER work dirty metal. Even dust contains enough grit to take the edge off tooling, just surface rust is like a sponge and holds lots of dirt. Wire brush thoroughly where you're going to drill, saw, etc. and your bits will stay sharp. Seriously I use a cup brush in my peanut grinder. 

Just buy a sharpening machine, it's hard to hand sharpen drill bits to a better edge. I can't see well enough to put a proper edge on drill bits anymore, I can get them to drill but they're not "Right." 

Here's one for you Marc. You have to drill holes in a piece of hardened steel but can't anneal it without ruining the piece. How?

You blade guys may know, if not you should. 

Frosty The Lucky.

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My grandfather taught me to use a dull drill or piece of round rod a little larger than the hole to be drilled. In the drill press run the rod/drill at high speed and apply pressure to get the area hot through friction, then switch to a sharp drill bit and drill it.

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Interesting question Frosty. The reply from IFC seems duable, anneal with friction heat rather than annealing the whole blade. it is still annealing isn't it?

You can also heat the tongue with an oxy and keep the blade cool with a heat sink or keeping it in water or being just careful.

Not my thing.

On 12/30/2018 at 5:34 PM, swedefiddle said:

Papy asked a question, I believe his question has been answered.

Neil

It's called conversation. i don't see this forum as a podium to lecture, rather a place to pass a few minutes chatting with others of similar interest. If I go over a topic more than once is because it interest me, and those that answer make sense ... or sometime do not ... :P

Frosty, why do you think cutting oil is not a lubricant? I quoted one of the suppliers I buy from, and there are a few more that supply industry, from automatic robots to old fascion fitters and turners workshops. They all list the requirements for a cutting lubricant according to what they are used for.

If cutting oil for industry is a lubricant among other things, it is a lubricant for my home pedestal drill any day every day. 

To say cutting oil is only a coolant is denying the obvious. We could go into how lubricants work and why, but I think it would go beyond the scope. The fact that you can get away with home made cutting compound, or that you can get away with not using anything is irrelevant. You can run an engine without oil in the sump if you first apply a solid lubricant like Molybdenum bisulphate or graphite and the engine is worn enough, and you don't push it past just above idle. That does not mean the sump oil is not a lubricant.  

Sure sharpness is very important. A Drill Doctor a good investment. Water is better than nothing ... and cutting oil is a lubricant ... oh ... yes and also a coolant. :)

By the by ... I have yet to meet an oil that is not a lubricant. 

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I run em dry.........Hole gets drilled out ok. All the HSS bits I have hold up great at the feed rate I run stuff, no problems. The truth is people usually run them way to fast...

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"The truth is people usually run them way to fast..."

A lot of people are using drills/drill presses that are designed for drilling wood and not steel.  Drilling substantial holes in steel require quite slow speeds and high pressures to be efficient!

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IDF&C: That is how I was taught. Friction heating with round rod is very localized, any torch flame will spread and heat a larger area than may be wanted.

Marc: This method doesn't reach critical temp nor have a long enough cooling time to qualify as annealing. I was taught to stop and let it cool when the temper ran to blue or a little bit past. I think it falls short of "normalizing" but close enough to do the trick. In the day we called it, "running the temper out," or, "running the colors."

I never said oil, cutting or otherwise isn't a lubricant. That would've been a foolish statement and unless I'm making a joke I try not to be foolish. Perhaps deliberately misunderstanding clear statements for your purposes of "discussion" is what some folk find tiring enough to speak out about?

What I said was, most cutters need a coolant and or the cuttings flushed from the cut far more than a lubricant. How much of a lubricant is water soluble oil? According to the literature when I was in high school the oil is there and formulated as a rust preventative in the coolant. I'll admit that is from memory nearly 50 years old but Mr. Harding our "occupational heavy metal shop" instructor was very specific about the subject. The occupational classes were to prepare students for careers and were heavily vetted by industries that hired kids straight out of high school.

We not only learned how to do various processes on industrial machinery we spent almost equal time in the books learning why things were done the way we were being taught. The only machines that had pumps were the mills and both were labeled coolant pumps, on the machines and in the manuals. Thee was the cut off band saw and it was drained and the pump disabled it ran a low feed rate and variable TPI blade so it didn't need a liquid bath to flush cuttings. 

We had to study the manuals and pass a test before operating any machine in the class. We had weekly safety quizzes and spot tests on the floor. 

Sharpened correctly, proper speed and feed rate are the most important factors for any cutting tool, any media. Get any one of the three wrong and a good lubricant will keep the cutter going a little longer.

Here's another pop quiz question for you. What is the correct drill bit increment when drilling over sized holes in annealed steel? As in pilot, to 1" hole. That would be with a home shop drill press, say 1 hp. that'll turn slowly enough to not damage the bits.

Frosty The Lucky.

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