Coolant/cutting oil on manual lathe

I apply coolant mixed with water from a spray bottle.

I try to use the coolant for all steel cutting except hack sawing and chamber reaming, when I use the stinky oil.

What's the "stinky oil"? I thought *that* was sulfur oil!

Does generic black cutting oil have sulfur in it? Is sulfur part of what makes "cutting oil" cutting, as opposed to lubricating? Anything other diffs?

There is natural sulfur content in fuel oils (depending on geographical source, I would imagine), which is the primary cause of acid rain--H2SO4. Some lakes have pH 5!! Like orange juice!! yummm.....

I wonder how one might test cutting oil effectiveness? Tool life?

Yeah, I use those spray bottles as well, except my Costco ones are 32 oz, really too big. Thanks for the link. I have found, btw, that some, maybe all those spray bottles lose the "spray", and will only "stream", above a certain flluid viscosity. fwiw. If you need the wide angle spray, you can dilute the pure oil w/ wd40, 'Blaster, kroil...

-- Mr. P.V.'d formerly Droll Troll

If it smells like sulfur is is ...

The thd cutting oil does.

Sulfur makes it work like nothing else. On SS try toilet water, then after all your tools have burned up try sulfur oil (but put in new tools first) VBG I just drilled 3800 303 parts .375 long .209 hole thru with ONE tin drill... Try that with toilet water .

--One trick: if you've got a long cut to make and the spray mist stuff is too thin, rig an old coffee can with a valve and attach a length of model airplane fuel line tubing or similar to it. Position the can high on the mill so it's got gravity to aid flow. Fasten the tube to the top of the spray mist nozzle, ending maybe an inch or two from the end. Turn on the heavy oil and it'll ooze down to the end of the spraymist without dripping, then it'll get blasted onto the part along with whatever mist you're shooting. I've done this many times and it beats the heck out of stuffing a brush in there every ten seconds for half an hour..

I use a brush for small amounts of oil and a pump-type oil can with a long spout if the work needs to be flooded.

Mike

I just "recycle" the plastic dishwashing soap bottles for that. I'm just basically "cheap".... :-)

Type F automatic transmission fluid works great for chamber reaming, esp. in stainless. Doesn't stink, either (or maybe my nose is immune....).

-jc-

PV:

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

=======================================================

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. =========================================================

BS, It will only stain soft metals like brass which I have been running by the 1,000's for 30 yrs "IF" you don't wash the days run in Naptha! Don't wait 2 days.

This is a particularly elegant solution! With or without spray mist.

If the tubing tip is attached to the cutting tool/toolpost itself, provides constant coolant at the cutter's edge, at almost any flow rate--depending on how high yer ceiling is... :) No motors, air, hassle. Just gravity! I probably will kluge up a loc-line ditty here. Too bad the smallest they make (I think) is 1/4"--but, they have pretty fine tips.

Oh yeah, and a pulley/rope for the can--I got high ceilings! :) Also could have multiple coffee cans, just switch lines around, for alum, steel, etc. Very nice!

Really really interesting!

I would, however, point out one logical inconsistency in the explanation below. In forming a "chemical bond" between the tool and workpiece, which "thereby keeps the tool from direct contact w/ the metal", I would say that you don't get much better "direct contact" THAN a chemical bond!!

I think what they *meant* to say is that the sulfur somehow loosely bonds the OIL to the metal(s), thereby keeping the two metals (bit/work mat'l) from *bonding to each other* under the high temps due to cutting, and thus preventing dulling. And might explain why sulfur oil is more effective on steels, because the S is bonding to both the tool *and* the material.

Uh, *covalent* bonds, in fact... :) :) (old, very inneresting amc thread...) Similar to the way sulfur vulcanizes rubber, also requiring high temps.

Sulfur is perhaps the most important element in the body's structural proteins (hair, muscle, skin, etc.), ito of forming their 3D structures (quaternary structure, in the parlance), via cross-linking--but mostly via sulfur-sulfur "bridges". For example, curly hair has more di-sulfide bridges than straight hair. Perms break these S-S bonds, thus straightening hair, but which will spontaneously reform, over time. What makes a fried egg "fried" is extensive S-S bond formations. Not reversible over time. :) Note sulfur in vulcanizing (cross-linking) rubber, as well.

Chlorine (or more accurately, chloride) is thought to be the culprit in embrittled SS, which is why SS is just so-so in marine applications.

So these effects of sulfur/chlor>>

Dave:

Yeah, they should have had their advertising copy proofread by a machinist that uses sulfur oil on a regular basis. LOL