stripped allen set screws

[dav-1]

i have a couple of set screws that are rounded enough that the right size allen wrench just turns and the next larger size won;'t go into the set screw.

   are set screws hardened? if so, will heating them with the flame wrench soften them up or make them harder?

 i want to save what they are in. i am hoping that i can drill them out. in the past i just cut stuff but now my pile of spares is dwindling, as is my cash flow, so i have to try to save stuff.

[PhanDad]

After soaking awhile in Kroil, I've had some success drilling them out with a left handed bit - if you're lucky they'll spin out.  I never tried heat.  

 

[Tarheel]

 You might try dipping the allen wrench in valve grinding compound then trying. The grit takes a good bite and has saved me many times.

[Tarheel]

 As to the heat ? The trouble with trying to soften most hardened steels is that it has to cool very slowly. As in hours.

To harden steel, it is heated to the point that the hardening agent (carbon, carbides etc) start growing crystals. At that point the metal is quenched to freeze the steel etc while the hardening agent is still in crystal form. To soften (Anneal), You have to bring the metal back to the optimal temp and then drop the heat very slowly so that the crystals shrink.

 This is way over simplified. There are a good many books on the subject and a good many types of hardened steels. This makes things even harder to figure as 1084 carbon steel hardens at a lower temp than say 440 stainless. What does happen most often when hardened steel is heated is that the temper is ruined. After a steel part is hardened, (most anyway) they are tempered to draw down some of the hardness and make them tougher. Again over simplified.

[Ronald Hribar]

Sometimes metric Allen wrenches fit better

[Bill725]

If you decide to drill out, the nice thing is the socket will center the drill. Find out with the tap drill size is for the threads. Select an easy out with a drill size smaller than the tap drill. Drill set screw and use easy out if necessary. Drilling the set screw reduces the wall thickness reducing the stress.

[Brettw]

In the past, I have started with some bad language, a few beers, and just stare at it a while.  I must confess, it has never helped, even a little bit, to loosen or remove the said part.  However, it does assist in getting up the motivation to attack the issue once again, and the contemplation, more than a few times, has come up with a solution.  Note:  The beer must be cold to properly assist in contemplation.  Just sayin'...........