Canola oil as a coolant ?

[cropwell]

I have just spent nearly £3k on a new lathe. The old one had a sudsoil system and I still have 2l of the undiluted stuff left. It stained the bed of the little bugger and the stuff turned green when I was machining brass (a lovely pale sage green). So I am a bit wary of water on machinery. I am using some surplus engine oil diluted with paraffin at the moment in a hand sprayer. This seems to have a good cooling effect but I don't like the idea of flood cooling with it. My reservoir tank takes about 10litres, so that is under £20 in budget engine oil terms and £8 for veg oil.

Vegetable oil (especially rapeseed) is £8 for 2x5l at ASDA and has several advantages :-

• It is cheap
• It has a high flashpoint and autoignition temperature
• It has good lubrication properties
• It is non-corrosive
• It is not carcinogenic
• It won't stain the machine
• You can buy it at most supermarkets
• It doesn't smell that much
• You can recycle it for bio-diesel
• And it's cheap.

So why does it not seem to be being used. Is the thermal transfer not good ?