r/Luthier • u/Mediocre-Comb2351 • 1d ago
Affraid I may have too much forward neck bow
Hey yal, Im doing my first amateur fret job here. Full fret replacement. Ive got no strings installed and no tension on the truss rod. Ive got some forward neck bow going on, and i know it need to be level before i level the frets. With no tension on the truss rod, i measured the gap between my high tech strait edge(yes i made it myself and ensured it sits strait by putting it on a window) and the 8th fret(which seems most center to me) and got a reading of .030" on the feeler gauge. With the truss right tightened down i got the gap down to .014". I cant get thos thing perfectly flat for my fret leveling job. Have i got a pretty big issue here or is this typical neck bowing? Thanks!
(Picture is with no truss rod tension)
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u/Frosty_Solid_549 1d ago edited 1d ago
It’s near impossible to determine relief with a full-length notched straightedge unless the fingerboard is trued perfectly flat. What’s likely going on is that the neck has an upturn at the end of the fingerboard like 99% of Gibson banjos which is giving you a mis-reading of there being relief when it’s very possible there is none. I’d cut the last quarter of that paint stick off, that way you’re measuring only the area that the truss rod practically effects
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u/JimboLodisC Kit Builder/Hobbyist 1d ago
do you know what relief is?
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u/Mediocre-Comb2351 1d ago
Isnt that another word for forward neck bow? Or is it got something to do with strings clearing over the frets to prevent fret buzz?
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u/JimboLodisC Kit Builder/Hobbyist 23h ago
Isnt that another word for forward neck bow?
Correct. And do you know how the truss rod affects this?
Or is it got something to do with strings clearing over the frets to prevent fret buzz?
That is called action.
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u/topholopho 1d ago
you can access the truss rod with the strings on? why not string it up, play it and adjust by feel/hight of the string
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u/Wilkko 22h ago
If I understood it correctly you already installed the new frets right? I would have checked the fretboard straightness before installing them to sand it straight if needed. Now it doesn't matter much.
What matters more now is the line that the frets form. Maybe there's no need to level the frets. You can check how straight the fretboard is with the notched thing when you are sure you are going to level them, not before.
If you want to know how straight or functional the line above the frets is, I recommend you to check it with the strings on. Check the neck relief the regular way with the 6th string (and all strings in tune) and try to adjust it how you want, then see if there's some issue with unlevel frets or unusual buzz. If there isn't you are done with it. If there are only a couple of spots that are not level you can try hammering the high frets down. If there's more then go back to what you were doing.
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u/The_B_Wolf 1d ago
Tighten the truss rod until the relief is zero. Tightening it will pull the neck backwards. Can you night tighten it more? It should easily be able to do this with no string tension on it.
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u/Mediocre-Comb2351 1d ago
When i had it tightened ealier(when i had that .014" gap measurement between the strait edge and the fretboard at the 8th fret) the truss rod nut had gotten pretty tight. Im afraid ill break something
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u/The_B_Wolf 1d ago
Try bending the neck backward a little while you tighten the rod. Your mileage may vary, but my philosophy is that if the truss rod can't be made to work properly, the instrument is toast anyway, so take a chance. However, that is my philosophy. You take the risks you feel comfortable with.
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u/Mediocre-Comb2351 1d ago
My main concern is: is this type of neck bow normal or do i need to take action against it?
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u/Marek_Galen 1d ago
Tbh. It looks like quite a bit. Like dude said, crank truss rod back until it’s completely flat. I like to smack the neck up and down the fretboard lightly to help manipulate it along. Get it flat and leave it to settle for a few hours. With no strings on it you can crank it to where there’s a very slight back bow to compensate for when you put the strings on. Or just leave it flat and readjust after you put strings on. Taking it to dead flat is a good starting point.
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u/mrfingspanky 1d ago edited 1d ago
Oh my god they MADE a notched straight edge.
You don't play the fretboard, and you don't need to measure it. In fact, you don't need a straight edge.
A more accurate method to gauge neck relief is to use the string. Capo at the first fret and press down on the last fret. A string is a better straight edge than a child's wooden ruler.
Also, yes. 0.014 is good relief for a banjo. Banjos have low tension strings, so they need that extra space to move in so the note is clean. You should only need to touch up the board. You probably don't have to relevel. I would say if it's pretty flat, and not twisted, but has that relief, do the minimum work needed.
You don't want to sand to far with a level bar and ruin something, or make a bigger job.
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u/NoShape7689 1d ago
Are you sure your 'straight edge' is actually straight. Not the best choice of material for one imo because it is prone to warping.