GR-1SF 12-String?

Is this possible?

I've been sitting on a GR-1SF kit and a pair of TV Jones Classics for at least a couple years now and starting to think about a summertime build. I'd like to do something somewhat unique and I've been interested in a 12-string for quite some time now. is it possible to plug and redrill the tuner holes on the GR-1SF headstock and fit 12 tuners? Are there particular considerations/potential pitfalls I need to think about in my planning (nut? bridge update? size/placement of tuners? issues with the "bigsby", etc?).

Thank for any insights/thoughts/experiences you can share.

Trem 12-strings simply don't exist AFAIK. I've never seen one. 12-string tuning is never the easiest of issues and fitting a Bigsby trem on a 12 string is asking for disaster. So you'd need to swap the Bigsby for a suitable 12-string trapeze tailpiece, or maybe a 12-string stoptail and drill a couple of holes for the posts. You'd need to swap the bridge out for a 12-string one as well, ideally one with individually adjustable saddles.

Then you have issues with the neck width and the headstock length. The PBG 6-string kits all seem to have a 42mm wide nut. Their 12-string models normally have a 45mm wide nut (IIRC). That 3mm difference may not sound a lot, but it can make a big difference between having strings that are too close to play and a playable set-up. Many 12-strings have a 48mm nut width to aid playability. Rickenbacker 12 strings have a similar narrow nut width, and you really need to have slim fingers in order to play one.

The headstock length is probably too short to fit 12 tuners on. You'd need to looking at the smallest sized tuners you can. Maybe even look at non-guitar tuners like the Grover 210 which are designed for pedal steel guitars and don't have a screw protrusion so are more compact. 18.5mm wide body, so you could fit 6 of them in a line in 111mm/4.4". But the tuner buttons would be touching and you'd never tune a string without knocking the tuners next to it and putting them out. So you'd need a wider spacing than that to be practical.

Otherwise you could think about slotting it and doing a Rickenbacker-style arrangement. Or mixing tuner types and having standard and banjo-style tuners. But you''d definitely need to get tuner dimensions and work it all out on paper first.

Or you could remove the existing headstock and graft a longer one on, capable of fitting 12 tuners on in a conventional manner. It would save plugging and redrilling. But you'd need to be confident of your woodworking skills, or have a friend who could do that for you.

But you really need to think about the narrow neck width first, which would be the main stumbling block for most people. You could make a 12-string, but then be unable to physically play it.

Simon. Thanks so much for the detailed response - This is why I enjoy reading this forum so much. You've given me many things to ponder that I would have otherwise stumbled on the hard way. Not dissuaded from building a 12 string - perhaps just not with this kit.

Cheers

No problem. It's a reasonable question to ask and it does make you stop and think. Most parts of it are do-able if you've got the mind and ability to do it, and are willing to have a go. But it's the neck width that's really the biggest issue. A Rickenbacker 360/12 has a nut width of 1 5/8", or 41.2mm. You can space the strings out more towards the edge of the fretboard, but it will still be pretty tight on a 42mm nut, with a much smaller distance between string pairs than you get on a 6-string.

I agree with Simon, the first thing I would try and do is to play a Rick 330/12 or 360/12 to see if you are comfortable with the smaller nut size. For my scratch built 330 copy I'm going with the Rick 660/12 neck dimensions because the nut is quite a bit wider and even though I haven't played a 330 or 360 I know that with large hands I am going to find it difficult. If you are ok with the narrow neck then as Simon has alluded to the most complicated part is the headstock. Also as a side note I'm not familiar with the construction of that kit so I'd want know that the tailpiece was secured into somewhere solid because a 12 string has significantly more string tension than a 6 string as well.