What Type Of Cutting Oil is correct

Sundossa12

Sundossa12

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I was wondering what type Of Cutting Oil is correct. Not even sure if my process is correct, but it seems to work. I’ve tried plain motor oil and seems to work, but goes on thick. I’ve also tried various machine oils. Even Synthetic Turbine Oil, I like this the best. Has good consistency and doesn’t make much mess. Here is what I’ve been using in no particular order, applied with a small brush.

Kroil
Mil Spec Synthetic Turbine Oil 7808
Motor Oil 5W-30
PB Blaster
WD-40
Chain oil (Only because I got a case free from a neighbor who was moving)
 
Sundossa12 said:
I was wondering what type Of Cutting Oil is correct. Not even sure if my process is correct, but it seems to work. I’ve tried plain motor oil and seems to work, but goes on thick. I’ve also tried various machine oils. Even Synthetic Turbine Oil, I like this the best. Has good consistency and doesn’t make much mess. Here is what I’ve been using in no particular order, applied with a small brush.

Kroil
Mil Spec Synthetic Turbine Oil 7808
Motor Oil 5W-30
PB Blaster
WD-40
Chain oil (Only because I got a case free from a neighbor who was moving)
Click to expand...

Hi, Sun,

A lot depends upon what material you are working, what material cutter you are using, etc. I have a mini-lathe and mini-mill, and generally take light cuts. I work most material dry. If I drill or single-point thread aluminum, I use WD-40. I know some people use WD-40 when turning, as well, because they report that it gives a nicer finish on the finish cut. I use Tap Magic Pro Tap when tapping aluminum, steel or brass.

Any time I'm turning and I think the cut is heavy enough to require it, I use Kool Mist sprayed on with an spray bottle. I am going to try brushing it on in the future. Kool Mist is a soluble oil; you mix it with water, and the water evaporates over time. Some people report that the residue can stain steel. I haven't noticed that.

Cutting fluid is generally more about cooling than lubricating. While I'm no expert, I understand that the lubricant is more about making it easier for the chips to clear the work than anything else. I believe that this is part of what improves the finish, but I'm not sure.

BTW, if you are using carbide tools, you're better off to use cutting fluid continually or not at all. Using it intermittently can cause a hot carbide cutting tool to crack, something that's not an issue with HSS.

I'm sure other posters more experienced that me will give you some excellent advice. Good luck!
 
Hi...

For drilling or hand-tapping holes in steel, nothing beats good old high-sulfur (aka Bar & Chain) dark oil. Believe it or not, sulfur is the enemy of metal but it works to our advantage when applied under high pressure. It actually weakens the atomic bonds of the metal and makes it easier to cut. -Not kidding, it's really true. In addition though, it provides a lubricant for good chip clearing...

WD-40 is decent for tapping and great for turning or milling aluminum but a lot folks use various versions of Tap Magic.

For all my lathe and mill work, I switched to KoolMist and never looked back. One of it's ingredients is a form of acetic acid (a form of vinegar) and it can cause rust if you don't keep your tooling lubed. I make a point of spraying the compound area, lathe chucks, mill beds etc with WD-40 and there has not been a problem. I have on numerous occasions, made a part and left it on a table without wiping it down and it will get surface rust a little faster than usual. The advantages are so great though (keeps parts cold and no mess whatsoever) I don't mind the momentary hassle of wiping things down with an oily rag or a quick spray with WD.

I was slowly getting poisoned from all the cutting oil smoke so, now it's only used for slow speed things that don't generate enough heat to cook oil.


Regards

Ray
 
First off, there is no real right or wrong answer. If you find something that works, use it. If you use motor oil, use a non-detergent oil, as this will be better for the machine in the long run.

In general, cutting OIL is either a High Sulfur Dark Oil or Mineral Oil. Dark Oil for ferrous metals, mineral oil for non-ferrous, and nothing for Cast Iron.

Coolant or Cutting FLUID, as it is commonly called, has really one function. Remove heat. The water-soluble oil in coolant is mainly there to keep the machine parts from rusting after the water evaporates. It may do a little bit to lubricate the cut, but not as much as oil

The Machinery Handbook has an entire section dedicated to cutting fluids and oils. In the 28th Ed. it starts on page 1114.

-Cody
 
Codered741 said:
First off, there is no real right or wrong answer. If you find something that works, use it. If you use motor oil, use a non-detergent oil, as this will be better for the machine in the long run.

In general, cutting OIL is either a High Sulfur Dark Oil or Mineral Oil. Dark Oil for ferrous metals, mineral oil for non-ferrous, and nothing for Cast Iron.

Coolant or Cutting FLUID, as it is commonly called, has really one function. Remove heat. The water-soluble oil in coolant is mainly there to keep the machine parts from rusting after the water evaporates. It may do a little bit to lubricate the cut, but not as much as oil

The Machinery Handbook has an entire section dedicated to cutting fluids and oils. In the 28th Ed. it starts on page 1114.

-Cody
Click to expand...

I've seen it being recommended using non-detergent oil for machines mentioned a few times on this site. Anyone know why this is?

I know that using non-detergent oil in a Model T is a good thing because detergent oil collects carbon which can short out the oil bath magneto.
 
DAN_IN_MN said:
I've seen it being recommended using non-detergent oil for machines mentioned a few times on this site. Anyone know why this is?

I know that using non-detergent oil in a Model T is a good thing because detergent oil collects carbon which can short out the oil bath magneto.
Click to expand...

The detergent in motor oils will keep any particulates, namely shavings, suspended in the oil. This is desirable in modern engines, where there is a filtration system at work. This keeps the wear material suspended until it gets to the oil filter, where it is captured and eventually removed. However, in machines if the particulates stay in suspension, they will act as a lapping compound, promoting wear on the bearing surfaces of the machine. This is why they are not recommended as lubrication for bearings, ways, etc.

To my knowledge, this is really the only reason, though I cannot believe that the extra chemicals would be good when they cook off of a hot part, if they are used as cutting oil.

-Cody
 
It all depends on what you're cutting. For aluminum, mild steel or brass, there are nice light oils on the market. Cool Tool II was great for this. That's one of my favorite cutting oils.

When you're taking deep cuts, tapping, or working with difficult materials (like Inconel, 316L stainless, titanium, etc.), nothing beats Huber's 318 from H & B Petroleum (AKA Habcool 318). Be warned: it smells awful right out of the can, and reeks badly enough to makes people nauseous if you get it hot, especially if you get it smoking. I've turned 3" tool steel down to 3/4" in 5 or 6 passes using this stuff, but the assembly women in the next room hated me for the rest of the day.

Good luck,

Rog
 
For machining nearly everything that one could think of, one can use any of the proprietary tapping fluids; I use Tap Magic for nearly everything; I'd eat it on my pancakes, if it tasted better ---- Just Kidding! One of my old bosses said that about white lead, and we used to mix it with black cutting oil and triclorethelene for threading. What I would definitly not use is any plain mineral oil, such as turbine oils or suchlike and motor oils; try the Tap Magic, and you will never need anything else for cutting; it works even on aluminum and does not stink like kerosine, the old standby.
 
A while back, I added Crisco to my cutting oil inventory. Now, I use it more than anything else. It works really well on aluminum, stays put until it gets hot, and doesn't make any big clouds of smoke. It never goes bad, since it isn't actually food. I haven't found any application yet that I wish I'd used something else.
 
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