On Wednesday, October 24, 2018 at 11:43:55 AM UTC-4, wrote:
On Tue, 23 Oct 2018 16:32:02 -0700 (PDT), wrote:

On Tuesday, October 23, 2018 at 1:47:51 PM UTC-4, Leon Fisk wrote:
On Tue, 23 Oct 2018 10:07:19 -0700
"Bob La Londe" wrote:

snip
Forgot the tapping fluid,
and I could feel the stainless starting to gall as I tried to start the tap.
Rather than walk back out to the shop I hit the tap with a shot of olive l
cooking spray and it worked. Maybe not as impressively as Tap-Magic tapping
fluid but good enough to tap a couple holes in some stainless sheet.

If I recall correctly "lard" was commonly used. If you find that round
tuit here is an old Machinery's Reference Book on Cutting Lubricants:

https://archive.org/details/cuttinglubricant00newyrich

All sorts of old concoctions you can experiment with

--
Leon Fisk
Grand Rapids MI

Note that the old reference book talks about lard OIL, not lard.

Lard oil is extracted from lard by separating it from the stearin crystals, which are the component that makes it stiff and pasty. It's the oil that makes good cutting lube. It used to be a common commodity because it was a cheap replacement for whale oil in lamps. The stearin was (and is) used in making candles, but it hampers cutting by keeping the oil from wicking into the cut.

Lard oil is not as good as modern chemical cutting soups but it's pretty good overall. I still use my old can of Buttercut, with was straight lard oil, for cutting ferrous metals on my lathe. I also use it for threading and tapping in applications that aren't highly demanding. For those, I have a couple of precious cans of 40-year-old Tap Magic. And for threading hard steel I still have a half-pint of carbon tet.

But we con't talk about that one. d8-)
That old precious Tapmatic stuff with the chlorinated hydrocarbon
solvent worked very well indeed. And you can get stuff that works just
as well today. It's made by CRC. It's called TrueTap EV. Instead of
containing trichloroETHANE it contains trichloroETHYLENE. It says on
the bottle that it works as well as the old stuff and it does as near
as I can tell. Especially on 316 SS.
Eric

I'll have to keep that name handy. Thanks, Eric.

--
Ed Huntress