To keep your broadheads from loosening off, and still be able to remove them without a fight, try putting some silicone sealant (like the buthtub goo)
on the threads-just a little bit.
ONce the silicone sealer has "cured," its rubberlike properties will stop the broadhead from coming loose, but when you need to remove the BH, the rubbery sealant will tear loose without the fight that lock tite, etc can cause.
This "trick" works for all screw in assemblies-its an old moto-cross bike prep trick (and probably drag racing, mudbogging, etc etc)
If you don't like this idea, finger nail polish makes a great removable thread locker.