Action On A Bass

[black_labb]

hi guys and girls

i am working on a bass and need to know what kind of action is typical at the 12th fret. i searched here and google, and only found one site which said that 2.4mm is typical at the 17th fret (which is 1.8-1.9 at the 12th assuming a perfectly flat fretboard). this didnt really seem right to me, and i couldnt find anything else on the subject. whats a good number to work to for low action (so i can get it there then raise the bridge to get it to the most suitable action) the bridge i have doesnt seem to have too much vertical travel so i want to be pretty close to where i want.

thanks for the help

[Jon]

It really depends on your playstyle, I prefer 3mm - 1mm string spacing on my 6-string bass. Try 2mm at the 12th fret and go from there, I adjust until I get rid of the fret buzz and find a comfortable spacing for each string.

[erikbojerik]

StewMac is a very good resource for stuff like this....of course, all in the context of adverts for their products.

SM's suggested string actions

[black_labb]

thanks for that, i seemed to think that it was going to be higher than that, ill get back to working.

edit:

i just tested the bridge, and there is really only aroud 2 mm of travel, which accouts for 1mm at the 12th fret.

looks like i might have to shim the bridge.

should i account for a bit of neck bow which will be present in the form of relief? id prefer not to have to use shims, so getting the correct height first up which such small travel on the bridge adjustment would be great.

Edited September 25, 2007 by black_labb

[erikbojerik]

should i account for a bit of neck bow which will be present in the form of relief?

On the StewMac page where they refer to "relief", that is the amount of gap between the specified fret and a straightedge that is laid along the fret tops with the strings tuned up to pitch (i.e. pulling on the neck with their usual amount of string tension). The only real way to measure this is with a good straightedge and a set of feeler gauges. If the frets have been levelled properly, the straightedge should sit on #1 and #12 (+/- a fret or two), and the maximum amount of neck relief should be seen around #7-#8-#9.

You need to tweek the truss rod (loosen strings, tweek rod, tighten strings) until you get the specified amount of neck relief, turning the rod no more than 1/8 turn each increment. Once you get close (or ON) the specified relief number, THEN work on the action (saddle height).

If you find that you still need to raise the saddle, two possibilities are:

(1) it is likely your neck is bowed (in which case you probably won't be able to get to the specified amount of relief with just the truss rod)

(2) if your neck is truly straight and tuned up right, then either your neck pocket or the body itself has some bow (throwing the neck angle off)

If you must shim the bridge then shim the whole thing, not just each saddle individually.

[black_labb]

should i account for a bit of neck bow which will be present in the form of relief?

On the StewMac page where they refer to "relief", that is the amount of gap between the specified fret and a straightedge that is laid along the fret tops with the strings tuned up to pitch (i.e. pulling on the neck with their usual amount of string tension). The only real way to measure this is with a good straightedge and a set of feeler gauges. If the frets have been levelled properly, the straightedge should sit on #1 and #12 (+/- a fret or two), and the maximum amount of neck relief should be seen around #7-#8-#9.

You need to tweek the truss rod (loosen strings, tweek rod, tighten strings) until you get the specified amount of neck relief, turning the rod no more than 1/8 turn each increment. Once you get close (or ON) the specified relief number, THEN work on the action (saddle height).

If you find that you still need to raise the saddle, two possibilities are:

(1) it is likely your neck is bowed (in which case you probably won't be able to get to the specified amount of relief with just the truss rod)

(2) if your neck is truly straight and tuned up right, then either your neck pocket or the body itself has some bow (throwing the neck angle off)

If you must shim the bridge then shim the whole thing, not just each saddle individually.

i understand that, im just wondering wether i should factor in relief when determining the height of the bridge, as there is little travel on the bridge and id prefer not to have to shim the bridge. i am only a bit into the build, but its a neck through and ive needed to determine some things already, such as how much i should lower the area the bridge is on.

[erikbojerik]

No, you should not factor in relief when you calculate bridge height, since it is really just a "dip" that lies below a straight line across the highest frets.