Official Luthiers Forum!

I was thinking about building an electric 12 string bass guitar. After I couldn’t find any plans anywhere for one, I was wondering if anyone on this forum knows how I should go about it. I’m guessing the neck has to be pretty sturdy, probably a truss rod with extra carbon fiber rods in each side. Does anyone else have any ideas?

Have you looked at what's on the market to give you some ideas? I'd have 2 truss rods if it was me.

_________________
"Act your age, not your shoe size" - Prince

I know that there is only a handful of manufacturers that makes them commercially. I guess I should look at their specs. I never thought about two truss rods. I can imagine that there is an insane amount of force from 12 strings.

If you are talking about a bass with four courses of three strings each, one primary in each course and two octaves I believe Dean makes one and possibly Ibanez. Spend some time with a good string tension chart and you'll know exactly what you need to do for truss rod(s) and neck joint. Well designed twelve strings guitars do not have "an insane amount of force" but it is higher.

Make sure you can source (or build) a bridge and pups, make sure you can fit the strings on your neck as well as tuners that will work with the strings you choose. A potential problem might be finding the octave strings long enough for the bass scale.

https://www.12stringbass.net/

This might be a good resource.

I think Hamer was the first to build one for the Cheap Trick bassist years ago. There are other makers out there, I'm pretty sure. It's not going to be impossible, but it won't be easy. Good luck.

_________________
"Act your age, not your shoe size" - Prince

There was a brief thread here a short time back

viewtopic.php?f=10123&t=53206

I think it will also be difficult to find a 12-string bridge. I’ve seen that some people have modified 4-string basses and their bridges to accommodate 12 strings.

Find a clever machinist and have one made.... Have a couple made and sell them to defray your costs.

_________________
"Act your age, not your shoe size" - Prince

Have you made any bass necks from scratch? Any 5 strings? You don’t need plans.

I made an 8-string back in the 80s. I couldn’t find a bridge for a 12.

I used two truss rods and a graphite rod between them. You might get away with one truss rod, but that’s a lot of tension.


Sent from my iPhone using Tapatalk

I haven’t made any bass necks before, but I have made several acoustic guitar necks. I was told to use at least five laminated layers for making a 12-string bass neck. I plan to beef up the neck with enough support so that it doesn’t flex, but should I be worried about the neck-to-body joint if it’s going to be a bolt-on neck?

My humble suggestion is to start by doing the calcs for the scale, strings and tunings that you want to use. Compare that to standard four, five, string string bases. If you have significantly higher tensions then consider how that will affect relief and neck joint. I build twelve string acoustic guitars, some with very long scales and very fat strings, but the tensions are all reasonable, the guitars are stable and very playable.

Until you've done the math you don't know where you are headed.

I didn’t have any problems with a bolt on neck, but make sure you leave the heel long enough.

This uses a standard Fender screw pattern and neck plate. The neck is 7 pieces; maple with walnut laminations.




Sent from my iPhone using Tapatalk