Recipe of the day: DIYSwede's Drilling & Tapping paste

Firstly: This isn't my original idea - neither am I opening a "-Which is the best tapping fluid?" can of worms.
Secondly: I sort of promised some sort of scientific/ research results to back my recipe up,
but I haven't been able to track back and find the stuff I saw a few years back.

So- without further ado - My personal go-to drill & tap paste:

-When you're makiing breakfast and fry your bacon - line a small strainer with a piece of household paper,
set atop a smallish glass jar already with about 25% (of the jar's volume) of ATF, DEX II is good enuff.
When finished frying, pick the bacon up and serve, then tip the contents of the pan into the strainer.
Let bacon grease filter thru and into jar. Put lid on and store.

Repeat this procedure 'til you've got the jar almost filled, then put beside the hot plate to melt contents.
Strain thru paper again if needed, let cool. Metal cap & class jar keeps rats, mice or pets out.

Apply the now reddish paste with a Q-tip or small brush when tapping or drilling holes.

ATF seems to avoid it getting rank, at least my latest batch hasn't in over two years.
Excellent for gummy stuff: mild steel, aluminium, zamak - It doesn't stain copper alloys.
Cheap, available and smells better than other fluids or oils when drilling.
Down side: Clean tap, drill and piece with a squirt of spirits if you don't dig that your stuff and shop will smell funny.
YMMV

That is pretty much lard oil, an old school standard.
I agree it work well, and safer than white lead...:confused:

A quick substitute is actually Crisco.
Used to cut a lot of aluminum and it really does help, doesn't go bad for a long time.

Years ago I worked for Sunnen Hones, they used to put lard oil in a pressure cooker, cook it for days until it was dark brown and thick as grease.
Bottled it up for sale as engine assembly lube. This was back in the late 70's
I don't know if it's still done that way anymore.

Thanks Moldyjim!
The now non-obtainable (at least for me - think it was from US DoD) research report,
did some extensive comparisons between commercial tap fluids, pure lard oil as well as bacon fat.
I seem to remember the quantified criteria was Tool torque, Thread surface finish & Tool wear.

The base line was white lead/ carbon tet - which still will make the very best thread, low torque and tool wear -
but is now for darned good reasons forbidden.
If the carbon tet won't get you terminal liver/ kidney failure and/or affect your CNS -
https://echa.europa.eu/substance-inf...fo/100.000.239
the white lead poisoning will probably get you: https://en.wikipedia.org/wiki/Lead_poisoning

Now- (I might be mistaken, of course) but the very result/ discussion that instantly caught this Cheapo's eye,
was the very good results for lard oil & bacon fat compared to commercial fluids,
where the bacon fat had superior properties to pure lard oil in gummy or "difficult" materials.

Discussion went along the following "logic" (if memory serves me right):
1) Dissolved sulfur in nearly any lubricant fluid will improve all three criteria above. Proved within study.
2) Lard oil doesn't contain any sulfur additives. Proved.
3) Bacon fat make cuts (somewhat or much - depending on material) better than pure lard oil does. Proved.
Now the bit of free-wheeling logic of Confirmation Bias:
-Hence the (natural or chemical) smoke additives of bacon, fried, should contain sulfur in the fat residues.
Discussion then went somewhat astray devising tests for that hypothesis.
Really bugs me that neither can I find the FOI act on this, nor remember which gov-lab did it and when.

Having had a bit of formal logic, epistemology and theory of Science myself, I'll (humbly - as ever) refrain from grading this,
BUT their proven results was good enuff for me, Bacon Fat works in tests, just like in my shop -
weak explanations, faulty logic, complacent researchers or not.
THEN - and here my Inner, sub-conscious Cheapskate hollers: -Its free!

Well - you don't have to agree with me on this, don't have to try it instead of that branded stuff you might have.
I don't particularly need "convincing testimonials from happy customers", marketing quotes or claims, or more Academic Strife.
I just try to share, as I think not everyone here have yet realized that reading MSDSs, lab research studies or PhD theses "is pretty sexy".
-Ah, yes: -English isn't even my native language, so please forgive my spelling and grammar.

No argument here, Carbon Tetrachloride is seriously nasty stuff.
My first crack at Tool & Die was at a place that made the carbide dies for the cans for Libby's, Anheuser Bush, and Coors (LiANCo.)
The boss was a real piece of work, used white lead in cutting fluid all the time.
Of course that was back in the late 70's, times have changed.

"-Ah, yes: -English isn't even my native language, so please forgive my spelling and grammar.[/QUOTE]

Seriously? your english writing is perfect, better than mine probably and I have had 6 decades of speaking it.