A technique you may try is to put the side of your hand on the body of the guitar and use the pudgy part of your hand in line with the pinky to roll the volume on and off by shooting your hand back and forth. I've seen many players do this for a song where they want that sound. No mods needed. Just a thought.
Ok. How fast do you need to flip it on and off? Like fast vibratto or slower? Depending on your answer you might try a pedal with no battery in it. So...when you are playing you leave the effect off, and when you want "killswitch engage - aaoooggaahhh" you step on the pedal and the signal is cut off.
Same idea will work with an a/b pedal if you have one.
Or, of course, you can just flip your pickup selecter switch back and forth if you have seperate volume knobs, but I assume you don't if you're thinking about a special switch.
Next idea. Take a guitar cable apart, or make one from a kit. Cut the cable really close to the input jack on the guitar and install a momentary cut button right there.
So what are you trying to get the killswitch to do for you I ask again. RATM stuff?
@macandkanga
I hate that site. The people think that they know everything and are some kind of gods.
Such as if you mention a killswitch, people talk about Tom Morello and will *** and moan that he has two volume knobs (one on one off) one tone, When Tom Morello Himself Always says he has one volume two tone with a 2way killswitch near the bottom cutout. (except his Les Pauls)
Plus many of the guides leave out important steps that doing wrong will kill your guitar or leave you with that Unplugged buzzing.