how to figure out where to drill for a bridge on a jazz bass

[Nigel Rahmshard]

I am getting an allparts body that i will be fitting an allparts neck to. The neck was used on another body and is already drilled so mounting the body to the neck should not be a problem. However i dont think there are any holes drilled for the bridge on the new body, aside from one for the ground wire.

How do i make sure i get the bridge in the right place for the proper scale length, and to make sure it is centered so that the strings pass over the pickups in the proper place. I am assuming the body is not drilled for pickups so i might have a tiny bit of leeway there. I am using a standard 5 hole bridge if that matters.

Any links you know of that would help me in the process would be appreciated.

Thanks!

[scottbass]

The distance from the front edge of the nut (the edge nearest the bridge) to the center of the 12th fret should be the same as the distance from the center of the 12th fret to the center of the bridge saddles. For a 34" scale bass, the distance from the front edge of the nut to the 12th fret should be 17", plus or minus a very small amount. Adjust the intonation screws on your bridge so that all the saddles are in the middle of their travel, then measure and mark the correct distance from the 12th fret. Position the bridge so the centers of the saddles line up with this mark. Install some low-tension cotton string or heavy thread to simulate your lowest and highest (thickest and thinest) strings, then move the bridge sideways (from left to right) to center the strings on your fretboard. Make sure the bridge is parallel to the frets (again, by careful measurement), mark the mounting holes and drill away!

[NickInMesa]

35" 1/16 from the nut to the drill hole (per Stew-Mac).

I know, I am building a J Bass as well.

[Nigel Rahmshard]

cool thanks for the info. I plan on poking around online to read up on some other peoples builds before i do the drilling. I'm looking forward to my "american made" custom bass!

[NickInMesa]

Nigel, by American made you mean American made hardware only?

If yes who did you use for your pickups? Lollar?

[Nigel Rahmshard]

I'm american and i am making it. lol. If i was a real manufacturer i suppose I should say, "Made in the usa" then "may contain foreign parts" in tiny letters.

Allparts neck and body, hipshot tuners, seymour duncan antiquity 2's, fender 62 ri bridge and control plate, fender mint green pickguard, cts pots, ernie ball strings. Probably almost all overseas made stuff in reality.

Maybe i'll just write "hand made" in big letters with an american flag background. That's a good trick manufacturers use....

None of the above really matters, it's all just a fun project since the bass i desire is a mix of different models.

[PaleMelanesian]

You should position the saddles all the way forward and set that as the 34" scale length point. The bridge will move farther from the neck / closer to the back end of the body when you do this. There was a discussion about this a while back, and NOBODY had ever had to adjust forward / shorter than the theoretical scale length. Setting the saddles at halfway is giving up half of your adjustment.

[scottbass]

Originally Posted by PaleMelanesian

You should position the saddles all the way forward and set that as the 34" scale length point. The bridge will move farther from the neck / closer to the back end of the body when you do this. There was a discussion about this a while back, and NOBODY had ever had to adjust forward / shorter than the theoretical scale length. Setting the saddles at halfway is giving up half of your adjustment.

Really? I'm not doubting you, but it somehow seems counterintuitive that all the variation in strings is in one direction. Now I'm curious - gonna go measure all my basses!

[NickInMesa]

Originally Posted by PaleMelanesian

You should position the saddles all the way forward and set that as the 34" scale length point. The bridge will move farther from the neck / closer to the back end of the body when you do this. There was a discussion about this a while back, and NOBODY had ever had to adjust forward / shorter than the theoretical scale length. Setting the saddles at halfway is giving up half of your adjustment.

And what if your fine tuning required to set the scale at, say, 33" 15/16?

[PaleMelanesian]

I'm not saying it's impossible, but the physics is against that. When you fret a string, you're stretching it. That raises the pitch. We compensate for that by lengthening the scale to bring the note back to where it should be.

You might reasonably give yourself 1/8" or so of forward adjustment, just in case.

[Son of Magni]

What PaleMelanesian is saying is correct. There is no reason the strings should ever need to be shorter than the scale length, only longer. Read the wikipedia article on inharmonicity if you really want to know the details.

[megadan]

I don't doubt the science, at all. I swear.
But I have had (cheaper) basses where I've run out of forward adjustment trying to get them to intonate correctly. If this is your first build, I'd leave yourself some wiggle room.

[Son of Magni]

Originally Posted by megadan

I don't doubt the science, at all. I swear.
But I have had (cheaper) basses where I've run out of forward adjustment trying to get them to intonate correctly. If this is your first build, I'd leave yourself some wiggle room.

Ok, so that's probably a case of either the bridge or neck being mounted in the wrong position (or you have some very defective strings).

The point is that the intonation adjustment is for increasing the string length. If you need to make a string shorter than the scale length that the instrument is fretted for then there is something else wrong that should be investigated.