Scale measurement

[mojobass]

So I’m thinking of having a go at build from scratch (something I’ve always wanted to try) anyhow, when measuring bridge placement on standard 34” scale do you take measurement from infront of the nut or behind or even centre point of nut? Thanks

[Velarian]

AFAIK it’s in front of the nut, which is where the break point of the string should be. 

[ikay]

3 hours ago, Velarian said:

AFAIK it’s in front of the nut, which is where the break point of the string should be. 

👍 front edge of the nut

[mojobass]

Cheers guys

[Joe Nation]

It's the length that the string vibrates over, so between the face of the nut and the apex of the saddle.

[EssentialTension]

Scale length = 2 times the distance from fingerboard side of nut (or centre of zero fret) to centre of twelfth fret.

 

Distance of bridge saddles from nut (or zero fret) will vary slightly from scale length (as given  above) due to differential of intonation on each string.

[Joe Nation]

Very true. Which brings about a whole other conversation about the mathematics of intonation, and whether frets should be in slightly different positions for each string...

[Andyjr1515]

The folks above are right to raise the issue of intonation, @mojobass as the intonation adjustment range on bridges can vary enormously.

 

None of the saddle apexes are going have to be set shorter than the scale length but the G will usually be the closest to the scale length (usually around a mm longer).  The saddles for thicker strings are usually set at progressively longer positions with the bottom E often 4-5mm longer than scale.

 

So to set the bridge, what I usually do is:

 

- I wind the G saddle fully forward and then back off a mm or two to allow a bit of wiggle room for fitting inaccuracies

- I check that the other saddles will adjust at least 4mm further back than this (if they don't, then sometimes that means the bridge will need to be tilted - but this is rare for bass bridges)

- I then set bridge so that the forward-wound G saddle apex is at scale length

- I pop a piece of easy peel masking tape along the front edge of the bridge so I don't lose that position and then hold a string from the G nut slot to the G saddle and the same between the E nut slot to the E saddle to make sure that the sideways position is central and that the strings are going to be equidistant from the fretboard sides.

- I double make sure that the front edge of the bridge is still exactly in line with the masking tape (it's very easy to knock the bridge off position when checking sideways position) and mark my drill hole positions

 

That way, I can be sure that all the saddles are going to be capable of adjusted back far enough to intonate correctly and that the top and bottom strings are equidistant from the fretboard sides   

Edited February 9, 2022 by Andyjr1515