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Cutting oil

techenthusiast

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What's a good alternative to the real stuff when using high speed steel bits? Does low speed cobalt bits require cutting oil too? Does cutting oil protect my bits better? Can anyone share some knowledge on cutting oils to someone who knows pretty much nothing about it? Thanks.


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zkling

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What are you doing? Why do you think you need cutting oil or fluid?
 
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techenthusiast

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What are you doing? Why do you think you need cutting oil or fluid?


Because when I do light fabrication like making a bracket the hole I'm drilling smokes by when I use my bosses cutting oil it doesn't smoke and when I drill through thick angle iron on the press he tells me to use his cutting oil but the label is all worn away... And now that I bought a nice drill bit set of my own that cost a good amount of money I want my bits to last. But I am uneducated in cutting oil. His is green that's all I know.


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Leaflessshadetree

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I use Kroil. As far as alternatives anything, even used motor oil, is better than nothing.

BTW: The "high speed' description on bits is compared to the old manual drills. When drilling metal keep the drill speed low. You should almost be able to count the revolutions. The bit should be "peeling" through the metal making little strips or chips.
 

Jason280

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I've been using random oil that I've pulled out of vehicles I'm working on, everything from recycled rearend oil to ATF and gear oil mixed.
 

uart

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What's a good alternative to the real stuff when using high speed steel bits?
I usually just use a 50/50 mix of used motor oil and kero. Since I drained my car's ATF a few months ago however, I've been using a 50/50 mix of used ATF and kero, which I think works a bit better.

Does low speed cobalt bits require cutting oil too?
Technically the cobalt bits (HSS Co) are even higher speed capable than regular HSS, so I'm not sure why you call them "low speed".

Remember however that reducing the speed of any bit will generally make it last longer. Particularly if you're currently "smoking" them at the type of speeds you're using now.
 
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bwringer

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I use Tap Magic EP Extra cutting fluid. It works with all metals, it's somewhat sticky and seems to hang around on the drill bit and in the hole a lot better, and it's a hell of a lot less messy than used oil. It doesn't sling all over the place.

http://www.tapmagic.com/TMepx.htm

I have an old green bean can with a magnet inside and a little brush next to the drill press. I squirt a little cutting fluid into the can and use the brush to keep the drill bit lubed. The magnet lets the can stick to whatever steel surface I put it on without getting knocked over.

There are specific cutting fluids for specific metals if you really want to get picky, and of course Tap Magic isn't the only brand out there. There's a foamy spray that really *****, since it totally obscures the work.

If the boss won't let you buy cutting fluid, then use whatever you can find. You really NEED lubrication when drilling metals, or you'll wear out your bits pretty quickly. Old-school lard (or bacon grease) does actually work quite well, but quickly turns rancid and stinky.
 
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astroracer

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I use Tap Magic for drilling and tapping, there is an incredible difference between tapping "dry" and using the cutting fluid. I also use Castrol Cutting Wax. It works well with the rota-broaches and hole saws.
Mark
 

pepi

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Because when I do light fabrication like making a bracket the hole I'm drilling smokes by when I use my bosses cutting oil it doesn't smoke and when I drill through thick angle iron on the press he tells me to use his cutting oil but the label is all worn away... And now that I bought a nice drill bit set of my own that cost a good amount of money I want my bits to last. But I am uneducated in cutting oil. His is green that's all I know.


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I found cutting oil at ACE HW easy to find, use it with my armstrong hacksaw, taping and drilling. In spite of what folks say or do not understand the cutting oil helps the tool work. It is a good practice and smart I might add.


Very simple to keep it from slinging, keep a small amount in a container with a hobby type paint brush. Coat the bit or area and have at it. If it starts to look dry when drilling back out dip the brush and coat the bit or put the oil in the hole.

Always a way to skin a cat.
 
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Ed ke6bnl

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we use some unknow brand of cutting like grease that was given to us for out hole saw and was able to use on 1.5 in hole saw to build and entire cage for our offroad baja bug. I wish I could read the label, in a small pint can and dark in color and sorta like a grease consistency. just about out now and have added some bacon grease and that has worked ok. I have some store bought cutting oil but I don't like it as much and also have some plumbing thread cutting sulfur oil that works great.
 

Steinmetz

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Because when I do light fabrication like making a bracket the hole I'm drilling smokes by when I use my bosses cutting oil it doesn't smoke and when I drill through thick angle iron on the press he tells me to use his cutting oil but the label is all worn away... And now that I bought a nice drill bit set of my own that cost a good amount of money I want my bits to last. But I am uneducated in cutting oil. His is green that's all I know.


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Simply put, the cutting oil prevents the tool from overheating and potentially seizing in the work. Since the tool is applied with significant pressure and is generating frictional heat, in extreme cases it may weld itself to the work without the oil to help dissipate the heat by boiling off. Think frictional welding and you have the idea...
 

bobcatdan

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I keep what ever engine oil I have laying around in my oil can. I use that or kroil for cutting. I try to use something almost all the time. I'd like to try tap magic, but never have. We have drill chill from Zep at work and I'm not impressed it.
 

Olafur

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Anyone using motor oil, atf, gear oil, rust penetrant xyz.. e.t.c has never tried this stuff. Plain and simple!
Can of this pays for it self very quickly in drill bits and time.

MRO_SHOP-50004710.jpg


I suppose there are similar products available in the US, this is made in UK.
 
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Steinmetz

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Chainsaw Bar Oil clings to the bit and stays put pretty good. Probably alot cheaper too. Used oils stain, fling off and make a mess.

Used motor oils generally contain water, some bearing metal (Babbit contains lead) and products of combustion. Don't use them for cutting.
 
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uart

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Used motor oils generally contain water, some bearing metal (Babbit contains lead) and products of combustion. Don't use them for cutting.

Good points. I always used to use new motor oil (mixed with kerosene) for cutting, but recently I started using used oil just because I've always got loads of it available and no other use for it (I take most of it for recycling of course). Is used ATF less objectionable?
 

zkling

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Because when I do light fabrication like making a bracket the hole I'm drilling smokes by when I use my bosses cutting oil it doesn't smoke and when I drill through thick angle iron on the press he tells me to use his cutting oil but the label is all worn away... And now that I bought a nice drill bit set of my own that cost a good amount of money I want my bits to last. But I am uneducated in cutting oil. His is green that's all I know.

That makes sense. Just curious as to what type of cutting you were doing. On the cheap, bacon grease does work, but if you are mostly doing drilling, the sulpher based pipe cutting oil can be found at most hardware stores is a good bet. WD-40 works well on aluminum, one of it's actual good uses. A small can of tap magic for tapping.

Beyond that grab a gallon of general purpose cutting fluid, but the upfront cost is going to be a bit more than the above suggestions. And please don't buy into the "super slow for metal" drilling idea. Use an appropriate speed for the material and bit size. Going a little slower to allow for setup limitations is one things, but being able to count the RPMs is just inefficient and actually a good way to shoot yourself in the foot.
 
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Fretters

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Anyone using motor oil, atf, gear oil, rust penetrant xyz.. e.t.c has never tried this stuff.

That would be incorrect. :D I have an almost full tin of that stuff sat on the shelf, and rarely feel the urge to use it. Paraffin is fine most of the time. I'll occasionally use that compound, but very rarely, and there's little difference I've ever noted. A blunted bit is far more detrimental than fluid type.
 

Fretters

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Going a little slower to allow for setup limitations is one things, but being able to count the RPMs is just inefficient and actually a good way to shoot yourself in the foot.

It doesn't hurt anything to go slow though. As Outlaw noted the other day, I do have a thing for hand drills. :D I do actually use them too, almost to the exclusion of any other type, and I've never been hampered by using one. A keen drill bit is the most important part of drilling.
 

Olafur

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That would be incorrect. :D I have an almost full tin of that stuff sat on the shelf, and rarely feel the urge to use it. Paraffin is fine most of the time. I'll occasionally use that compound, but very rarely, and there's little difference I've ever noted. A blunted bit is far more detrimental than fluid type.

Fair enough! I respectfully disagree. :beer:
 

Fretters

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It may make more difference when running at higher speeds, but for how I drill, (I'm not saying it's not any good, btw, as it is good stuff), the main benefit over paraffin for me is simply that it holds onto the swarf better, like grease would.
 

zengarage

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I use rapid tap for tapping and a spray bottle of coolant that came out of the CNC mill for large drill bits but nothing on bits under 1/2" I have been using cobalt bits lately but my bits last a long time like that. To me you shouldn't need oil on mild steel. I only use the coolant because I want to get done quicker so I push it a little. I just drilled 12 holes 17/32" with a 1/4" pilot hole and a hand drill through 1/2" thick angle iron with no oil and the bit is not noticeably duller than when I started. And the only green stuff I know of is A-9 which is to keep aluminum from sticking but I would guess it works as cutting oil also.
 

Olafur

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It may make more difference when running at higher speeds, but for how I drill, (I'm not saying it's not any good, btw, as it is good stuff), the main benefit over paraffin for me is simply that it holds onto the swarf better, like grease would.
You have to excuse my ignorance but I am not sure what you mean by "paraffin"!?

Are you referring to mineral oil in general or something else?

Ps
I got to know this Rocol "RTD" compound 25 years ago when I was helping my uncle making interiors for several liqueur stores. This involved drilling several thousand 6 mm holes into 4mm mild steel. All done by the same HSS bit, but my uncle did sharpen it few times. Unfortunately I have never been good at sharpening drill bits.
 
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Steinmetz

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Good points. I always used to use new motor oil (mixed with kerosene) for cutting, but recently I started using used oil just because I've always got loads of it available and no other use for it (I take most of it for recycling of course). Is used ATF less objectionable?

Probably.
 
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techenthusiast

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Should I be using something even for redoing threads with a tap???


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thebeekeeper1

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I haven't used it much yet, but I got a bottle of green stuff at Fastenal that works well. It's the consistency of pudding so it stays in place, even when drilling overhead. I'm pleased with it so far. :)
 

Vegaman_Dan

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Been using ATF/Acetone for a while now. What I need to do is fab up an oil drip system with flexible tubing for my horizontal band saw. Was thinking of a plastic squeeze bottle, 1/4" clear tubing, and a couple of valves- one on the output and one at the top of the bottle (While inverted so it's coming out the flat bottom) to act as a vent. The only inline valves I can find for those sizes are irrigation drip valves. While cheap, they aren't quite what I have in mind. I may have to hit a hobby shop for valves used in RC airplanes, or a good pet store that has brass valves for aquariums. I really would prefer brass in this situation.
 

Fretters

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Paraffin is such an ambiguous name.
http://en.m.wikipedia.org/wiki/Paraffin

It is. We are quite consistent in how we use it though, but it can be confusing nonetheless. Paraffin = Kerosene. Liquid paraffin = the medicinal oil, (can't remember the other name for the stuff), and paraffin wax is the white candle wax. Confusing much? :D


Should I be using something even for redoing threads with a tap???

It doesn't hurt to keep the tap lubed regardless of application. You're not generally applying much stress on the tap when cleaning threads, but I tend to still dip the tap in paraffin or oil before running it through.
 
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