esteemed bass builders:string height at first fret ?

[Gregory nangle]

hello,
novice newb builder here, want to get better action on my builds. i know there was thread somewhere here about this topic ,but i couldnt find it. what is a good string height at the first fret and at the 12th fret? the bass i am working on has a 33.25 scale, 20 frets. 4 string. is .12 too high at the 12th fret? any advice thanks!

[David King]

Gregory,

Start with the neck almost straight via the truss rod adjustments with say .020" relief over the 7th fret (when the neck is capoed at the first and twentieth fret). Push each string down between the second and third frets and tap the string down over the first fret. The nut slot should be low enough so that there is just a barely perceptible gap between the string and the first fret. At the twelfth fret I would use the allen key the adjust the bridge down until there is just 1/16" between the fret and the string. A 1/16" allen key makes a fine height gauge. The E string will want to be a touch higher.

[Gregory nangle]

david,
thank you, ,can you explain this part? i dont follow:
"Push each string down between the second and third frets and tap the string down over the first fret."
everything else makes perfect sense! thanks!
-gregory

[Brian Evans]

You are using the string as a straight edge to see the relative height of the fret plane and the nut slot since your goal is to set the height of the nut slot to equal (or be just barely higher than) the height of the fret plane. You press down between the second and third fret (Bb on the G string) and look at the string height as it passes over the first fret. The space between the string and the first fret should be minimal - less than .010" and even less than .005". If you look and see a minimal space, you can tap the string and hear it click as it hits the first fret. I personally use a pick and "play" the string over the first fret. I want to hear the string note change as I fret at the third fret (Bb) and at the second fret (A) and pick near the nut. String tension plays a part in this - low tension strings sometimes vibrate in a wider path with normal playing vigor so you leave a little more space so you don't get rattle when playing an open string. Equally playing style can play a part - a player who plays fast and articulate smooth jazz lines might want a lower action than someone who pops and slaps a lot.

FWIW I have just lately been re-doing the nut height on a couple of guitars. I set them to be exactly equal to the fret plane. A seasons worth of humidity changes and string buzz on the three strings. Now I go for a few thou. higher than I used to, to allow for a bit of change with time and weather. I also set the lower strings higher than the upper strings, to allow for more string motion.

[Gregory nangle]

awesome, thanks for the explanation,now i get it ,very helpful! my basses are cast aluminum necks so the truss rod adjustment does not exist, since there is no truss rod, i put that .020 of relief in the castings on a mechanical surface plate and then mount the fingerboards to that surface. also my finger boards are now screwed into the neck via teh fetmarkers, makes it real easy to attch teh fingerboard without it moving all over the place when gluing. thanks again!