Here is a little photo sequence showing homebrew use of oil-hardening steel, also known 
as O-1 (sometimes with “drill rod” attached to the name).

The machining is done in the annealed (purchased state).  It machines nicely like a high 
carbon steel, a little tougher than cold-rolled, but not by much.

The feature(s) you want to be hard are heated a dull-red with a torch and quenched in 
oil…in my case I use “quenching oil” purchased at McMaster-Carr.  It can be reused over 
and over, as it is not damaged or consumed in the process.  I like it as it doesn’t flame as 
the red-hot part is plunged into the oil bath.

The part should be swished/stirred in the oil for approx 30 seconds, then taken out to 
cool.

The heated part, now quenched will have a black scale on it.  Now it is time to use 
scotchbrite or fine sandpaper and polish at least one area back to a silvery color (not hard 
to do).  You can convince yourself the part is hard at this point by dusting it with a 
file…the file, which will peel off metal in the soft state, will skate right over the hard 
surface.

I degrease the parts, finishing with rubbing alcohol which evaporates completely.

Then, into the kitchen oven 8-).  I use 500F for my setting, experience will tell you where 
to set it, but 450F is probably a bottom point to start at.

The color to shoot for is a “straw” or golden color, see the 2nd picture..  These parts 
(camlock spindle T-wrench and a 4-jaw chuck wrench) are finished.  A final polishing 
and they are ready for work.

Matt Isserstedt
11June2006