Jon Weaver wrote:

I want to harden a piece of steel, and from my school metal work days,
I think that I can simply heat it to red hot and then plung it into
'oil'

Is this the right? If so, what sort of oil should I use.. Are we
talking normal engine oil, or there there a special kind??

As you can tell, I havn't really got a clue what I am talking about,
so any info would be appreciated

Jon

There is a special recommended oil and the temperature of the oil is of
importance too. IF the oil is too cold you may get stress cracks. Also
there is a rule that you should have a certain volume of oil for each
pound of metal you quench or the oil temp will go too high. Keep the
piece suspended in the oil rather than throwing it in a tank so there is
even cooling around the whole piece.

Some others probably have more exact numbers for you. I usually use air
hardning stuff because I hate the smoke.

John