12 string bridge- string spacing?

[radioactive]

Does anyone have the spacing measurements for notching a 12 string bridge; the distance between each pair, and the octave from
the main, etc.?

I bought one of the new 12 string bridges and it arrived yesterday, so I'd like to put it to use. I've worked on many Gibsons before and have all the tools and files.

I know there's an old post from about 8 years ago, and while it has some great info on what files to use for each gauge, and aligning the bridge plate, I was unable to find much about string spacing.

Thanks! Rob

[beatlefreak]

If I'm not mistaken (and you have an R tailpiece on the guitar), you should install the bridge under the strings and mark where the strings fall across it. The nut and R spacing should set the spacing on the bridge.

[radioactive]

Thanks for the info! I'm putting the 12 string bridge on a 360/12v64, which has the older style U shaped bridge, so I don't know if that makes any difference from the R tailpiece.
My reason for wanting the exact measurements is that I read an old post from Mark Arnquist that details how he goes about notching the saddles on a 12 string bridge, but his post doesn't include the spacing measurements as far as I can decipher.He does explain what gauge files to use for the different gauge strings, and he apparently does all the notching and file work in a small vise with the bridge removed from the guitar. He states that the final work comes out very straight and even, which is what I want to accomplish.

Here's a link to his old post from August, 2000:

viewtopic.php?f=13&t=7139&hilit=+12+string+bridge

[clementc3]

It looks like there are two slightly different answers in the original 2000 thread, and they both are based on the distance between the paired (low and octave) strings. They use the joint between the pairs of saddles as the centerline of that distance; the distance beween different strings (E to A) then solves itself. (I copied the following items from that 2000 thread):

Answer #1:
by Mark Arnquist (markthemd) on Sun Jul 01, 2001 7:46 am
I use dial calipers to notch the saddles and I do this off the guitar .

As the center of the pairs is a given measurement,I spread the strings to .090 .I set my calipers to .045 and use a utility blade to scribe the saddles.The caliper edge is used to press the blade against .This gives a really accurate spacing.
(End of Answer #1)

Answer #2:
by Gary R. Smith (grsnovi) on Mon Sep 06, 2004 5:40 am
Seth -

You can plop the 12 saddle on the existing plate however you need to know if that plate is in the right place 1st. With the six saddle bridge, are any of the saddles all the way back against the inside of the bridge channel? If so (likely the low E string) you will want to move the bridge plate back towards the tail.

As to cutting the slots in the saddles - if the bridge plate is correctly centered, you can simply slot the saddles equally in from the side representing the center of the pair. With your string ceneters approx. 1/8" this would make your notches about 0.062" in. I've done two twelve saddle bridges. Somewhere I posted a rather detailed description to the web (not certain what the URL is at the moment). You could email me at [email protected] - put RIC 12 in the subject line or I'd just toss it and I'll email it back to you.
(End of Answer #2)

It looks like Mark Arnquist uses 0.090" and Gary Smith uses 1/8" = 0.125" between the paired (low and octave) strings. The string spacing at the nut might give you some guidance, but I don't know that for sure - I have personally punted to a qualified professional for my 12-saddle bridge installations.

Good luck!

[jingle_jangle]

In fact, when I do a raw set of 12 string saddles, I vary the string spacing a bit. Now, you can be ultra-precise and use the .090" figure, but laying it out using a caliper and utility knife, you will actually end up with your string spacing at around .080", give or take a few thou'. This is because of two inaccuracies: even when wearing a 10X Opti-Visor, and placing those calipers so they hang up on a scribe made by a utility knife (read: #11 XActo), you're a bit short, and scribing again using the inside the jaws flat as the guide, the center of the resulting scribe mark will fall short of the flat again. That's a double error of a few thousandths each time, so unless about .007" is added to the desired figure, giving an .097" caliper opening, the slot spacing won't be as exact as it sounds.

Nor does it need to be! We can go tossing around exact-sounding numbers all day long, but here's what I use, based upon observation of how a Rick 12 string electric guitar acts when strummed and picked. With a set of factory strings, tuned to standard E pitch, using even .090" spacing, and noting the unique scale length, it will be noticed that the only time the low E doesn't strike its octave partner is if it's picked very gently, whereas the high E pair has no such issue. The B pair and G pair also have no issues with this scenario, but the D and A can, although not as severely as the Low E pair.

So: I set the high E and B, a bit narrow, at .080" (with filing and marking, this can and does vary a bit), use .090" for the G and D, .100 for the A and .110 for the low E.

.125 spacing leaves way too little between the string pairs and will feel awkward to almost all players. .090" is too narrow for the low E and A pairs and perhaps a bit wide for the high E and B.

This is fussy stuff, but works well for 90% of players.

[clementc3]

And Jingle-Jangle is THE qualified professional for me! Thanks, Paul!

[radioactive]

Thanks for the very detailed info!! It's exactly what I wanted to know. Appreciate your help, Rob