"DougC" wrote in message
...
On 5/5/2011 12:00 PM, John Doe wrote:
Has anybody tried using DuPont's Teflon silicon spray for a drilling
lubricant? Is it too lightweight?

http://www2.dupont.com/Products_and_...se/silicon.jpg

I am using canola oil right now I apply with a dropper bottle, as I ended
up with some I wouldn't be using for cooking at all, and there was no
local source of real cutting fluid in small quantities.

The canola oil definitely works better than nothing, and it doesn't cost
much and it doesn't smell at all in use--but it probably doesn't work as
well as "real" cutting fluid would either.

It's worth finding a supply of real cutting lubricant, Doug.

Cutting oil attempts to do a couple of things at once: Provide high-pressure
lubrication, and prevent skating of the cutting tool. These two objectives
are at odds; certain oils and additives are better at it than others.
Sulfur, for example, provides some lubrication at extreme pressure but it
also has a threshold, above which the film punctures, and lets the cutting
edge in to do its work.

Most cutting oils are not really very good lubricants. An extreme-pressure
lubricating oil would be much better. But it could make your tool skate over
the work, particularly with lathes that have less than production-quality
stiffness. Flexible tools or workpieces can produce the same result on *any*
machine tool.

Until I came to this NG I had no idea that serious hobbyists did so
much...uh, experimenting, with all kinds of industrial and kitchen liquids.
g You may come up with an effective one every once in a while, but the
commercial products made for the job usually will beat them.

I realize it's not easy to find good cutting oils these days, and that a lot
of users mix up some pipe-threading lubricant with a little kerosene or
whatever as an expedient. I haven't seen DoAll's cutting oils for sale for
quite a few years now. They came in quart cans. But you can still get
Buttercut, I think. That's straight lard oil, one of the first cutting oils
used for machining. It may actually work no better than your canola, but it
does do the job.

Note we aren't talking about "coolant" here. On small machines, lubricating
usually is far more important than cooling.

--
Ed Huntress