On Wed, 27 Sep 2017 08:55:30 -0700, wrote:

On Tue, 26 Sep 2017 18:07:34 -0400, Ed Huntress
wrote:

On Tue, 26 Sep 2017 14:39:19 -0700, wrote:

On Tue, 26 Sep 2017 16:27:01 -0400, Ed Huntress
wrote:

On Tue, 26 Sep 2017 12:29:43 -0700, wrote:

On Tue, 26 Sep 2017 09:18:37 -0700 (PDT), "
wrote:

On Tuesday, September 26, 2017 at 11:54:32 AM UTC-4, wrote:

Any thing is better than nothing. Your hydraulic oil is not going to be the best possible, but will probably be about 90 % of the best possible oil/coolant.

Dan
Actually Dan, hydraulic oil makes lousy cutting oil, not even close to
being 90% as good as the best possible cutting oils or coolants.

Eric

Thanks for the correction. For years I have used what ever is handy including ATF. And believed it was much better than nothing.

Dan
Maybe better than nothing, but certainly not as near as good as
cutting oil. Have you tried bacon fat? Even bacon fat is better than
motor oil. Seriously.
Eric

With all of the stearin in it, it won't wick by capillary action. When
you take the stearin out you're left with lard oil -- which has a
decent set of properties (and a very long history) as a cutting oil.
Bacon fat wicks OK when the metal is good and hot. BTW, how is the
stearin removed? I have always wanted to make lard oil.
Eric

The traditional process is to heat lard to some specified temperature
(or color); then refrigerating it to around 30 deg. F for several
days, allowing the stearin to crystallize and separate from the oil,
and then squeezing it through a fabric filter under some modest
pressure to filter the stearin crystals from the oil.

Modern industrial processes started by 1850 to improve the efficiency
of this separation. I have no idea what they are. The demand for lard
oil originally was for lamp oil, to replace whale oil and sperm oil.

It has good wicking ability, high-pressure resistance, and about the
right amount of lubricity (you don't want too much, or tools will
skate) for cutting oil. It was sulfated from fairly early times to
improve its high pressure resistance.
I think I'll try the old method Ed. I have been wanting to get some
lear lard from the butcher and render it myself for holiday cooking
this year. Might as well get some lard oil for the shop too. Years ago
I used an aluminum tapping fluid that was mostly lard oil and
deodorized kerosene. It also had a really strong perfume added that
made me almost gag after I used it for a while. Kinda like the Simple
Green perfume. I can't stand the smell of it anymore.
Eric

I'll bet that you can find some better details on lard oil separation
somewhere around the Web. I didn'd look. I'm running on memory from 40
years ago, when Plant Operations (including cutting fluids) was part
of my beat at _American Machinist_. I learned about lard oil from the
old books we had in the McGraw-Hill library, which had accumulated
since AM was founded in 1877.

At one time is was something that was done on farms, so there should
be plenty of info on the low-tech approach, if you can only find it.

BTW, I still use Buttercut straight lard oil for turning steel on my
old South Bend lathe -- which I have to clean up and get back to
using. It does have a unique...er....aroma.

--
Ed Huntress