My Dear John -
what Quixote said
when I was young and stupid I used what every hobby blacksmith used: used crankcase oil.
it stank,
it smoked & flared,
you needed to keep a steel lid handy to put it out.
those with sense and dollars used the cheapest high-temp vegetable oil they could get.
even used french fry oil is good !
veggy oils are non-toxic, smell LOTS better, and work real well.
the point of oil vs water quenching is the viscosity, or thickness - it boils away from the metal more slowly and does not cool the piece as abruptly.
one still needs to keep a lid handy. and a modern fire extinguisher.
Oh, and do it outdoors or in a garage or shed with the big door open.
NOT the basement, don't ask.
for little bitty hammer faces a liter or so of cheap canola or peanut oil should be plenty.
save it in a marked bottle for later projects.
yhs
prof marvel