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I would like to know more about lard oil. I'm not sure but, black sulphurized thread cutting oil, seems to be a recommended replacement.

Bob Swinney

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They're not direct replacements, Bob. What is it that you want to know about lard oil? It's been around for a century or two. It's just lard that's been chilled until the stearin crystallizes, which allows the oil to be pressed out of the goop and drawn off.

The lubricating properties of lard oil and unmodified mineral oil can be similar, but the additives and some of the synthesized components used in mineral-based lubricating oils give lubricating oil and cutting oil radically different properties. Oil made for lubricating has properties that are not good in a cutting oil. Motor oil is lousy cutting oil. It's made to

*prevent* local contact under high pressure, although its ability to do so is limited at cutting-tool pressures.

Heavy thread-cutting oils have good cutting-oil properties except that they don't get into the cut in a machine tool, so they don't do anything in a deep cut. You want something that gets in there. Plain lard oil and the non-lubricating mineral oils, formulated for cutting, will do that to some degree. However, research (done mostly at Carnegie-Mellon Univ. in the

1950s) shows that they don't get into the cut as much as some people have claimed over the years.

Basically, you want a cutting oil not to squeeze out under pressure, but you want the film to puncture easily upon point contact. These are somewhat contradictory properties but there are some additives that will help do it, including white lead and sulfur. There are modern replacements for these.

Beyond that, there are chemical additives that actually get into the crystal structure of the workpiece and help separate the grains when they're cleaved with a cutting tool. Chlorine compounds will do this on some work materials. So will carbon tetrachloride. Chlorine has been taken out of most cutting oils because it forms carcinogenic compounds at the tool/work interface, where the temperatures are locally very high. Carbon tet was never used in commercial cutting fluids. But it was tested extensively at Carnegie-Mellon, and the way it works is amazing. Unfortunately, it tends to kill machine operators. d8-) I've used it. Some gage makers used it on hardened steel, a century ago. They're all dead now for various reasons. I'm on borrowed time myself.

Modern high-performance water-miscible cutting oils ("soluble" oils) contain chemical additives that are safer and that have some of the properties of chlorine in a cut. Blasocut and other fancy-schmancy oils rely heavily on the properties of these additives, I've been told by their vendors. I'm not much interested in them for hobby work so I'm not up to date on these fluids.

Plain lard oil, like Buttercut and some others that are still on the market, are fine for the hobby shop. So are the simple mineral-oil cutting oils that DoAll and such have sold for decades. I think that cooking up your own, or using slop like used motor oil, is false economy and may be dangerous.

-- Ed Huntress

Geeze, Ed ! Thanx for the information; esp. the research timeline. My curiosity re. lard oil comes from reading old books and articles. Its use was apparently de rigueur in the old days. I have not found any modern definitions of the term, except for yours. Personally, it is more of a historical curiosity with me. I generally use Tap Matic for turning and the Black Sufphurized mess for threading. Bob Swinney

They're not direct replacements, Bob. What is it that you want to know about lard oil? It's been around for a century or two. It's just lard that's been chilled until the stearin crystallizes, which allows the oil to be pressed out of the goop and drawn off.

The lubricating properties of lard oil and unmodified mineral oil can be similar, but the additives and some of the synthesized components used in mineral-based lubricating oils give lubricating oil and cutting oil radically different properties. Oil made for lubricating has properties that are not good in a cutting oil. Motor oil is lousy cutting oil. It's made to

*prevent* local contact under high pressure, although its ability to do so is limited at cutting-tool pressures.

Heavy thread-cutting oils have good cutting-oil properties except that they don't get into the cut in a machine tool, so they don't do anything in a deep cut. You want something that gets in there. Plain lard oil and the non-lubricating mineral oils, formulated for cutting, will do that to some degree. However, research (done mostly at Carnegie-Mellon Univ. in the

1950s) shows that they don't get into the cut as much as some people have claimed over the years.

Basically, you want a cutting oil not to squeeze out under pressure, but you want the film to puncture easily upon point contact. These are somewhat contradictory properties but there are some additives that will help do it, including white lead and sulfur. There are modern replacements for these.

Beyond that, there are chemical additives that actually get into the crystal structure of the workpiece and help separate the grains when they're cleaved with a cutting tool. Chlorine compounds will do this on some work materials. So will carbon tetrachloride. Chlorine has been taken out of most cutting oils because it forms carcinogenic compounds at the tool/work interface, where the temperatures are locally very high. Carbon tet was never used in commercial cutting fluids. But it was tested extensively at Carnegie-Mellon, and the way it works is amazing. Unfortunately, it tends to kill machine operators. d8-) I've used it. Some gage makers used it on hardened steel, a century ago. They're all dead now for various reasons. I'm on borrowed time myself.

Modern high-performance water-miscible cutting oils ("soluble" oils) contain chemical additives that are safer and that have some of the properties of chlorine in a cut. Blasocut and other fancy-schmancy oils rely heavily on the properties of these additives, I've been told by their vendors. I'm not much interested in them for hobby work so I'm not up to date on these fluids.

Plain lard oil, like Buttercut and some others that are still on the market, are fine for the hobby shop. So are the simple mineral-oil cutting oils that DoAll and such have sold for decades. I think that cooking up your own, or using slop like used motor oil, is false economy and may be dangerous.

-- Ed Huntress

** Posted from **

Old, obsolete information is my specialty. It fits my overall character. d8-)

Aack! Do you use old phone books for toilet paper, too? Tap Magic is fairly nasty stuff -- at least, the original formula is. And it eats aluminum. Maybe their newer versions don't. They have many versions of it now.

Anyway, the Original is 90% 1,1,1 trichloroethane. Here's what they say about it in their MSDS:

INHALATION: Minimal anesthetic or narcotic effects may be seen in the range of 500-1000 ppm. Progressively higher levels over 1000 ppm may cause dizziness, drunkenness; concentrations as low as 10,000 ppm can cause unconsciousness and death. In confined or poorly ventilated areas, vapors which readily accumulate can cause unconsciousness and death. These high levels may also cause cardiac arrhythmias (irregular heart beats).

SKIN CONTACT: A single prolonged skin exposure is not likely to result in absorption of harmful amounts. The LD50 for rabbits is about 15,000 mg/kg.

INGESTION: Single dose oral toxicity is low. The LD50 for rats is greater than 10,000 mg/kg. If aspirated (liquid enters lung), may be rapidly absorbed through the lungs and result in injury to other body systems.

Those are just the short-term (acute) effects. There are other long-term (chronic) effects. If it were me, I'd find another cutting fluid for use on a machine tool, and reserve the Tap Magic for tapping.

-- Ed Huntress

What I have is Tap Magic. I don't use if much for turning; mostly tapping. It contains none of the

1.1.1. Trichloroethane bad stuff.

Bob Swinney

Old, obsolete information is my specialty. It fits my overall character. d8-)

Aack! Do you use old phone books for toilet paper, too? Tap Magic is fairly nasty stuff -- at least, the original formula is. And it eats aluminum. Maybe their newer versions don't. They have many versions of it now.

Anyway, the Original is 90% 1,1,1 trichloroethane. Here's what they say about it in their MSDS:

INHALATION: Minimal anesthetic or narcotic effects may be seen in the range of 500-1000 ppm. Progressively higher levels over 1000 ppm may cause dizziness, drunkenness; concentrations as low as 10,000 ppm can cause unconsciousness and death. In confined or poorly ventilated areas, vapors which readily accumulate can cause unconsciousness and death. These high levels may also cause cardiac arrhythmias (irregular heart beats).

SKIN CONTACT: A single prolonged skin exposure is not likely to result in absorption of harmful amounts. The LD50 for rabbits is about 15,000 mg/kg.

INGESTION: Single dose oral toxicity is low. The LD50 for rats is greater than 10,000 mg/kg. If aspirated (liquid enters lung), may be rapidly absorbed through the lungs and result in injury to other body systems.

Those are just the short-term (acute) effects. There are other long-term (chronic) effects. If it were me, I'd find another cutting fluid for use on a machine tool, and reserve the Tap Magic for tapping.

-- Ed Huntress

** Posted from **

Pardon, make that 1,1,1, trychloroethylene. The label on the can says it has none.

1.1.1. Trichloroethane bad stuff.

Bob Swinney

Old, obsolete information is my specialty. It fits my overall character. d8-)

Aack! Do you use old phone books for toilet paper, too? Tap Magic is fairly nasty stuff -- at least, the original formula is. And it eats aluminum. Maybe their newer versions don't. They have many versions of it now.

Anyway, the Original is 90% 1,1,1 trichloroethane. Here's what they say about it in their MSDS:

INHALATION: Minimal anesthetic or narcotic effects may be seen in the range of 500-1000 ppm. Progressively higher levels over 1000 ppm may cause dizziness, drunkenness; concentrations as low as 10,000 ppm can cause unconsciousness and death. In confined or poorly ventilated areas, vapors which readily accumulate can cause unconsciousness and death. These high levels may also cause cardiac arrhythmias (irregular heart beats).

SKIN CONTACT: A single prolonged skin exposure is not likely to result in absorption of harmful amounts. The LD50 for rabbits is about 15,000 mg/kg.

INGESTION: Single dose oral toxicity is low. The LD50 for rats is greater than 10,000 mg/kg. If aspirated (liquid enters lung), may be rapidly absorbed through the lungs and result in injury to other body systems.

Those are just the short-term (acute) effects. There are other long-term (chronic) effects. If it were me, I'd find another cutting fluid for use on a machine tool, and reserve the Tap Magic for tapping.

-- Ed Huntress

** Posted from **

** Posted from

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Ed,

Us old-timey sign painters used lard oil in large amounts for preserving lettering brushes, (flats, quills, fitches). It was able to remain fluid in nearly any temperature, it kept any residual paint from hardening in brushes, it would wash out easily, and even if you didn't wash it out completely, it did not adversely affect the lettering enamel. Good stuff!

Flash

Well, that's good. I think they still sell their Original formula, but they have at least a half-dozen others now.

-- Ed Huntress

That's one I hadn't heard of. I have heard they used it as lamp oil in lighthouses. Pigs in those days must have been in high demand. d8-)

BTW, a friend of mine makes a great brush soap, used for fine-art brushes and oil paints. It's called "Ugly Dog Soap." Have you heard of it?

-- Ed Huntress

On Tue, 5 Aug 2008 00:04:14 -0400, with neither quill nor qualm, "Ed Huntress" quickly quoth:

That's OK. They always did breed like rabbits.

Y'know, I'll bet that if we used hollow point bullets (stuffed with lard, of course) in Iraq and Afghanistan, we'd find fewer folks to shoot at.

I just googled it and found it at Blick. I prefer pink soap conditioner because I prefer acrylics to oil. I hadn't heard of UDS before now. Your friend must be rich. That shit's EXPENSIVE for linseed oil. ;)

-- A great preservative against angry and mutinous thoughts, and all impatience and quarreling, is to have some great business and interest in your mind, which, like a sponge shall suck up your attention and keep you from brooding over what displeases you. -- Joseph Rickaby