starrett tool oil is comprised mostly of mineral oil. norton stone oil is mineral oil that is 'highly refined', & approved for use with food.
can plain mineral oil be used as a tool oil, & stone oil? does starrett & norton (& other manufacturers) add special ingredients that change the oil to make it substantially better?
can i take (food grade/or pharmaceutical grade) mineral oil, & add something to improve its performance as a tool or stone oil?
I used to run a Hardinge chucker and we had a gov
aerospace job that called for LARD oil on the blueprint .We had to drain and clean machine before running the job. After running the job we had a job that I ran about every three months. And as there was a big hurry to get on the job
I ran it with the lard oil that was still in the machine. When the job was finished we found that by looking at past job records the job had taken about 30 percent longer than the last 5 times the job was ran. I think it was due to the drills and tools not lasting as long with the lard oil. From then we always changed back to the regular cutting oil. It is hard to run a test like this on a manual machine. Best to test with
a automatic machine. But the job cards showed just about the same times for the 5 times I had ran the job in the past. jims
Disaster Area --
In the early 1900s USP Mineral Oil was often used as a lubricant for fine, light-duty use. Although not as good a lubricant as correctly-refined sperm whale or porpoise-jaw oils, the mineral oil was less expensive and didn't stink to high heaven.
Today, USP Mineral Oil is as good a lubricant as it ever was, and it's not toxic so it's safe (although I don't know if it's USDA approved) to use as a whetstone lubricant when sharpening knives used to prepare food.
On the other hand, USP Mineral Oil has never been a superior lubricant; it does not contain any anti-wear or corrosion-inhibiting additives found in today's better lube oils.
Most PM Regulars seem to have a soft spot in their hearts for Mobil oils . . . we just plain like Velocite, DTE, and Vactra . . . but equivalent oils from any of the major oil companies work better as general-purpose lube oils than does USP Mineral Oil. The drawback to these oils is simply that they're packaged in big packages (think 5 gallon pails, only sometimes in 1 gallon jugs) and stocked only by petroleum distributors (although many "professional" auto parts stores can get them).
But there IS good news. Most grocery stores, gas stations, auto parts stores, and discount stores sell Automatic Transmission Fluid (ATF) in 1 quart bottles for a couple of bucks. Any ATF meeting General Motors' Dexron II, Dexron III, or Dexron higher-number specification makes a good general-purpose lube oil that will serve most needs at least as well as Starrett's Tool & Instrument Oil.
The only two downsides to using Dexron ATF in this way that I'm aware of are 1) ATF is NOT "food safe", and 2) ATF contains dye that will stain any lighter-colored thing it sinks into.
I prefer something thinner than USP Mineral Oil when using a sharpening stone. It's "too good" a lubricant for honing. In honing, you really want something that floats away the swarf, not a lubricant. So, you want somnething THIN.
I've been using dish detergent for honing knives. It's great, usually leaves the stone cleaner than when I started. No odor to transfer to food, either. If it's too thick, such as Dawn brand, just add water.
If I've honed a tool, it gets a separate rust-preventive after the soap is washed off and the water dried.
I've heard of people using WD-40 or kerosine as a honing oil for stoning tools, but keep in mind that it is smelly. The smell might linger on the stone and cause problems if you use it on a food knife later, even with some other lube.
For sharpening knives, I like the King Japanese water stones. They are soft, but cut really well. The 800 and 1200 grit are nice. The 6000 grit is a little too soft for my liking.
I've never tried the Shapton stones: http://www.shaptonstones.com/
I like this little quote from their site: "Sharpening is an attempt at perfection. The most interesting aspect of sharpening is the reflection of the infinite."
The food grade oil qualification is to allow cooks to sharpen their knives without worrying about contamination.
For stone oil you can't (or at least "I" can't) do better than 50/50 30W engine oil and kerosene.
If by "tool oil" you mean machine tool cutting oil there are so many various specific fluids out there you pays your money and you takes your choice.
I use diesel fuel both as parts cleaning solvent and as cylinder honing oil, mostly because of price and availability.
Solvency is not great. Keeps honing stones clean
For hand sharpening tools on a flat stone, flooded or dry. The surface speed is not such as to require coolant, so the purpose is to keep the stone from loading. A little of any fluid makes mud, which clogs the stone.
Dry, most swarf can be blown off with air, or scrubbed out with a pink rubber eraser.
Flood of light oil is even better, but messy to work under.
Aerosol engine starting fluid (used to be ether)works as a stone cleaner, too
When you say "tool oil", I am presuming that you mean cutting oil. Very few cutting oils work in steel as good as a high sulfer oil like Mobil Gamma. Another good high sulfer oil is Rigid Dark cutting oil. There are certainly other fluids that work differently in other materials. There is not one oil that "does it all".
Cutting oil does 2 things; cools the work and provides lubricity. Honing oil adds a third and that is to keep the stone clean. I never thought that there is much difference until I used Gessweins and Sunnens hone oil. Talk to somebody that does mold polishing if you don't believe me.
Gesswein Stoning Oil
Oil is oil, mineral or organic, when it comes to sharpening. The presence of any oil in stoning is preferable to no oil. The job of the oil is as a surfactant to separate and suspend the swarf as its generated and to seal the actual cutting away from oxygen on a microscopic scale.
An oil's lubricity, (its property for keeping metal surfaces from physical contact and preventing abrasion) is contrary to the fundamental concept of "stoning" where a bonded abrasive is deliberately rubbed against the metal to abrade it. Therefore: discount the term "lubricates" when applied to a stoning oil. If the oil under consideration truly lubricated stoning would be impossible.
Organic oils are usually superior for stoning compared to straight mineral oils but mineral oils can be compounded to improve their stoning properties. It's the peripheral properties of the various oils that determine their over-all suitability for stoning. Some oils oxidize over time when exposed to air in the presence of finely divided metal. Many vegetable oils will do this particularly those that have been heated like boiled linseed oil which may be handy at the moment but if used in stoning will clog your stones permanently.
I prefer a light machine oil for stoning. Any light machine oil will do be it spindle oil or hydraulic. I prefer light because it wipes off easier and for no other reason. Heavy bodied oils seem to persist leaving an unpleasant film on edged tools that need to be clean when put to use.
One of my favorite stoning liquids is not an oil but plain old spray-on kitchen cleaner like Fantastic or 409. It suspends the swarf, cleans the stone, wipes off easily, and the residues dry quickly. Countering that: it's hard on your hands and, since it's water based, will suck heat out of the work on evaporation, an important factor when stoning high precision surfaces prior to gaging or bluing in.
Another favorite of mine is WD40. It has excellent stoning properties but if left on stones will form a film that tends to clog the pores. Be sure to wash them in mineral spirits at the end of the work session.
I also like mineral spirits, kerosene, or barbeque starter fluid for stoning. While its surfactant properties could be better it's easily removed and its residues won't contaminate the stones. Ronsonal lighter fluid is another favorite I use for stoning precision surfaces. It has a low heat of evaporation, excellent surfactant properties, powerful cleaning properties, and it dries rapidly.
Don't get lost in manufacturer's claims. Be skeptical. If you yield to manufacturer's claims (of any kind) you will soon be lost to confusion and inner conflict. Starrett stoning oil is good stuff but expensive and actually no better in practical terms than any other light mineral oil. Their advertising claims may be the actual targets of product development but when tested and compared to competing products their alleged superiority becomes dubious to the observer.
Experiment and observe your results closely.
I think he is asking whats the difference in the oil Starrett makes for precision instrument oiling which is "Mineral oil" and Norton honing oil which is "Mineral Oil" as well. [img]smile.gif[/img]
At work we use the "Super Oil" stuff from the five and dime for sharpening chisels. Seems to work pretty well, as it's thin (thinner than 3 in 1 oil).