Vegetable oil as a cutting oil for machining?

[Frank S]

I have never used any of the animal fats or vegetable oils for coolant and lubrication in machining, mainly because for the past 35 to 45 years I have always kept Chevron soluble oil B or another brand on hand But mostly the Chevron product. The mix ratios can vary from 15 to 1 to 50 to 1 depending on application. When I had several machines running more or less constantly I bought it by the 55 gal drum Now I only keep a 5 gal pail on hand I've had the same pail for over 3 years, @ $70.00 to 80.00 per pail it is the cheapest solvent or lube I've found Since currently none of my machines have flood or spray units working on them I just mix up a 2 ltr. drink bottle with a small hole in the cap

[Toolmaker51]

Subject of much discussion, here and wherever metals are cut. There is science, primarily chemical and physical attributes that allow different selections to perform. No surprise, a lot of marketing/ salesmanship are at play too.
These are arranged in mechanical order of; producing a chip, cooling the chip, expelling the chip, achieve and preserve surface finish, maintaining stable material temperature. Often, attaining just one of first four, or combination of three produces satisfactory results. The material in question, operation performed + speeds and feeds, and tool condition are a greater part of the equation.

a] Friction is a product of machining. Primary effect is reduction of surface tension of material present when tool engages chip. The desired effect is a film on part and cutter to prevent chip welding itself to either. While termed 'lubricants' that is really secondary. Descriptions of lubrication/ friction/ heat overlook the mass of a bar vs the chip; temperature change of bar is minor compared to chip. Why motor and especially gear oils are poor cutting fluids; and worse yet to run engine on cutting oil!
youtube.com/watch?v=4cykOPKpaTw add www. to the link; I'm just saving space, adding suspense. But 23 seconds in, it and my avatar are one, channeling as it were.


b] Removal, absorption or separation of heat. Whether dripped, brushed, mist or flood, some better in heat control than fluids to improve cutting. At serious feed rates, blue chips all over the floor proves dry cutting can succeed. Sometimes all required is compressed air; nozzle and velocity lower relative temperature and flush chips very well. Introducing fluids produce the same effect; and an unintended shower for operator.

c] Smaller particles can get pressed between workpiece and tool; sufficient heat will rebond them to workpiece. Certain materials have that tendency as well, where no speed + feed combo want to alleviate that. That is incorrectly diagnosed as poor finish. In reality, it's metallization occurring. Tool sharpness, height from centerline, setover, rotation vs travel direction, and lack of clearance contribute to that first. Rebonding is just evidence.
In production environments, tests and history are results determining what occurs next time. Small shops more driven by availability and expense, and issues from exotic materials don't enter. Lard, vegetable oils, kerosene, bar oil, bee wax, soapy water; all work likely by producing a film with varied cooling rates. Tool conditions, operation performed, and machinability factors though are primary.

d] Finally, material temperature. Heat expands material proportional to mass. The majority of HMT is not industrial sized projects; yet use industrial processes. i.e. Expecting hot weldment to run immediately in a lathe or drilling could be unreasonable, equivalent heat vs small project.
300 stainless and free cutting brass run easily; where 316 [work hardens] or phosphor bronze/ copper alloys can be irritating.
Then there are situations where heat is not primary in the same sense. All conditions have to be balanced.
Low 1000's CRS is not all that machineable, you can get size yet finish can be problematic. Yet 12's and many tool steels and alloys are a dream to run.
Aluminum same deal; low T's require razor sharp honed HSS and lower speeds than T5 & 6 plow it like mad with ease, mill T7 trying to guess what planet it comes from...an unnamed moon of Holimolithius?

Most coolants are recoverable, even spray mist as in milling. Most mills have pipe threads in each end of table. Commonly; cans are suspended below for what flows out. I perforate a thin plastic container [like yogurt] as a separator. With holes pierced from outside wall, above the bottom, the 'barb' traps floating matter, and coolant flows through. Lathes have screens to accomplish separation. Grinding presents a problem in abrasive and micro-chips fouling pump vanes. Those are separated by dam-like arrangements with spillways, usually 3 and sump for pump. The 1st wall is notched high in the wall to force any kind of dense matter submerge. Successive walls are notched likewise but somewhat lower. Grinding typically uses water based emulsions and evaporates. You'll know by looking or when coolant flow slows to nothing, replace water and back to business.

[smithdoor]

The down side to most dark cutting oils (AKA sulfur, minimal oil, lard and kerosene) is the smell and keeps the wife away.
The upside dark cutting oils to does work well keeping mosquito and bugs away.
FYI I was buying for shop 55 gal drums of oil two or three times a year. I even would one year Blender with transform oil to lower the cost.

In my home shop today, I use a shop vac today and dry but I have look in to putting the shop vac outside the shop. The sound and any smoke will be gone to wind. The upside keeps the wife a lot closer today and the MD doctor happy too, avoid using dark cutting oil.

So using vegetable cutting oil sound great

Dave

[Moby Duck]

FYI I was buying for shop 55 gal drums of oil two or three times a year. I even would one year Blender with transform oil to lower the cost.


Dave

Transformer oil is expensive compared to regular cutting fluids. If you got it cheap it is probably because it was drained from transformers containing oil containing polychlorinated biphenyl's (PCB). This organic animal and environmental toxin was banned from new production in most countries in the 1970's but there are still lots of transformers containing PCB's out there, including some of the small bar shaped ones in fluorescent light fittings. Disposal of oil drained from these transformers, or disposal of sealed transformers, comes with a cost, and unscrupulous companies may sell the oil off cheap to unsuspecting customers. The use of transformer oil blended into regular cutting oil was not a good idea.

[Hans Pearson]

I thought I'd give it a try today an it seemed to work good. (so far) The normal cutting oils make too much smoke so I got this idea. I used it today on the lathe with some 1018 steel and not a bit of smoke from this! It didn't even give off much smell at all.

Would like to hear what others think about using this. Good? Bad?? What other things have you tried?

I also use a Silicone aerosol spray sold as Fuch Ecocut SC 14 here. Not too expenive and very convenient to use. I am sure there should be a similar product available where you are.