"Robert Swinney" wrote in message
...
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.

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

I generally use Tap Matic for turning and the Black Sufphurized mess for
threading.
Bob Swinney

Aack! Do you use old phone books for toilet paper, too? g 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