I deer for a capo

[Rob Mercure]

Howdy folks, I've got an idea I want to share and if someone managed to perfect I I'd like credit for the idea and a working model (yeah, my hopes are "modest" ). Now this wouldn't be useable on every guitar but for those Martins made when they warrantied their necks not to warp that came with the square tube neck reinforcement ("truss rod") I wonder if someone couldn't use one of the finger crusher "neo" magnet coupled somehow to a ferrous metal bar that would "bear" on the square rod below the fret board. This would allow capo action with nothing blocking the back of the neck. The idea seems quite feasible to me as I've already used a cylindrical magent to clamp three strings on my D-25K. But the "rub" is being able to easily remove and reposition the assembly. If I had a machine shop I think I could make a good stab at this but since I don't I'll throw it out and see where it lands.

Can't wait to try one if you'all manage to work it up.

Rob

[Russell Vance]

Good luck with your idea - the way we use to neutralize magnetic pull to remove these magnets from their task is to use another similar magnet in a holder, place it on the other magnet and manoeuvre it to neutralize the magnetic pull (sort of like magnetic 'phase cancellation') - this is how machinist magnetic blocks are held and released to/from magnetic work surfaces.. Alternatively, if this is difficult to do , simply place another bigger magnet oriented to attract the magnet in the capo on the back of the thing and pull it of with blunt force (how you wish to separate these two super magnets is then your own problem). Neither of these things are perfect but they are places to start from.

However, I'm a little concerned that by magnetising your truss rod (which is effectively what you will do) you will change the string vibration pattern - you have ferrous cores in your strings and your plains are all ferrous material and they will be affected by the proximity of a magnetic field running the length of the fingerboard. Whether, in practical terms this makes a difference, I don't know, but it's something you will need to take into account when testing this idea. Rusty.

[Rob Mercure]

Russell,

Yep, I thought about the magnetization issue - I've been an electronics tech, among other thing, for over 30 years, and it is similar to "degaussing" a CRT or other item. So if I can actually find the resources to fool with this (ya never know) I could always run my 300W soldering gun along the fret board or even wind a custom degaussing coil. Easy stuff for me but I'll admit is could be challenging for others with differing background and definetly worth considering if anyone can make this work and considered commercializing the idea (the biggest limit being that there are only a few guitars that it would work with - if at all). To be honest my primary interest is having one for me ! Thanks for considering it.
Rob

[FRANK]

electromagnet?

[Tommy Kay]

I think this may be worth a mention here? Dan Erlewine built a guitar with a cool backless capo system. He used threaded inserts that screw into the center of the fingerboard. He made several different size capos that covered any number of strings making open tunings possible without re-tuning. This was Telecaster style guitar and the various extra capo sizes are stored directly into the body edge. Very clever!

[Frank Ford]

That hole-in-neck capo is at least a century old concept, and I suppose it never took hold because of the holes. As to the magnet capo, while there is a small possibility you could set up a strong enough magnet to do the job, handling the magnet would be a life-changing proposition. Magnets that strong can cause steel things (knives, for example) to jump rather impressive distances to do serious damage to fingers. . .