On Wed, 01 Feb 2006 18:54:50 GMT, BottleBob wrote:

"Proctologically Violated©®" wrote:


Is sulfur part of what makes "cutting oil" cutting, as opposed to
lubricating? Anything other diffs?

PV:

Here's an explanation on what function Sulfur and Chlorine serve in
cutting oils, from a cutting oil manufacturer.

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http://www.sunnysidecorp.com/metal_working_oils.htm

Sulfur.

This additive performs an anti-wear function in cutting oils by forming
a chemical bond between the cutting tool and work piece, thereby keeping
the tool from coming in direct contact with the metal being cut. There
are two types of sulfur additives, active and inactive. The inactive
compound is used for cutting mild (low-carbon) steels and will not stain
these softer materials. The active sulfur forms a stronger bond than
the inactive but will stain soft metals. So, oil containing active
sulfur is recommended for cutting and broaching the harder varieties of
steel only. The object of this chemical bond is to promote longer
tool life and to keep the tool from welding itself to the work piece
under the severe temperatures created in many metal cutting operations.


Chlorine.

This additive works in the same fashion as the sulfur additive and
tends to complement the sulfur by strengthening the chemical bond (film)
around the tool. For this reason you will often find this additive
used cutting oils that contain a sulfur compound. Chlorine tends to be
liberated to the atmosphere at elevated temperature; therefore chlorine
additives are not particularly useful for extremely high temperature
applications.
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All,
I'll point out that such compounds are ALSO added to synthetic and
soluable oil types of cutting fluids. So are some others.
Why do you think that badly maintained water-based cutting fluids
can stink? The bacteria are degrading/metabolizing the compounds.

See:
http://groups.google.com/group/alt.m...e=source&hl=en
--
Cliff