Re: Bolt knob soldering
lead/tin solder won't do it, it's definatlly not strong enough even if it does stick.
Like was mentioned above brazing or tig is the way.
If brazing clamp a vise grip on the handle below where you are working for a heat sink.
If you get the handle to hot it can weaken the handle to bolt body brazing.
This must be the Tac-Ops knob kit.
Tig welding will be much nicer if your not going to paint the bolt,however it will require making a new stud out of appropriate stainless material.