Acoustic guitar advice needed

[Geek99]

Could anyone with an acoustic guitar please tell me what gap they have at fret 12 holding first and last fret? 
 

I still have forwards bow and the truss rod isn’t willing to go further. I’ll leave it overnight. Holding fret 1 and fret 14 I have 2mm at fret 6, I read that it should be nearer 0.9mm

 

am I right in thinking that sanding down the bridge bar is the only way to reduce action ? It’s electro acoustic and a standard new bridge bar so started out too high, just seem to be taking a lot off for the pickup filament

Edited November 7, 2023 by Geek99

[PaulThePlug]

Might have a shim under the bridge bar or piezo element?

But, likely to just get a load of buzz higher up, need to have a look at the relief before nut and action.

1mm or so might be good for a heavy strummer, but 2mm sounds like making issues for string height, intonation etc.

 

Action 2mm at the 12th... but not relief 2mm at the 6th

 

String Gauge?

[Geek99]

10-50 light

ill check under the piezo, hadn’t thought of that. The other acoustic I got had two toothpick fragments in there. I don’t know why, I got perfect relief and super low action without them

 

the neck may be screwed, but equally it was abandoned and unstrung for a few years so may ping into life with some time 

[Geek99]

It’s got too much forward bow, so I’m trying to reduce that by turning the truss rod nut clockwise. 

I think that’s correct 

[Geek99]

Measuring the other guitar I think the bridge bar is about 3mm too high owing to the piezo and also the new nut needs to be slotted lower

 

Edited November 8, 2023 by Geek99

[Frank Blank]

Paging @Andyjr1515

[Geek99]

The neck relief doesn’t seem to have shifted. I loosened the strings and left it near a radiator to see if the back bow kicked in. 
 

this isn’t for me btw, I have not turned to the dark side 🤮

[Geek99]

I think the truss rod is maxed out clockwise but I cannot see any movement in the neck - had expected middle frets to touch strings when first and last frets held but not so. Is that possible in a maxed out situation ? 

[Andyjr1515]

19 hours ago, Geek99 said:

Holding fret 1 and fret 14 I have 2mm at fret 6, I read that it should be nearer 0.9mm

 

This is a better way of measuring the neck relief.  From the heel onwards to the dusty end, the neck doesn't bend and so measuring from the last fret will give a misleading result. 

But yes, 2mm is a bit high.  Ideally, it wants to be a 'just perceptible' gap although 0.9mm would probably be OK.

 

And yes - for most guitars, clockwise on the truss rod will bend the neck towards a back bow to counteract the 'bow and arrow bow' effect of the string tension, thus leaving (ideally) the neck 'almost' flat. 

 

So, is the 2mm relief with the truss rod fully tightened as you describe, using the midpoint between the 1st and 14th?  And, if so, if you then loosen the trussrod by, say 1/4 of a turn, does that gap increase to greater than 2mm (in both cases with strings tuned up to pitch)? 

 

 

Edited November 8, 2023 by Andyjr1515

[Geek99]

It doesn’t seem to shift much

i got the guitar with a flat neck and a slack feeling rod-nut. It’s gone tight now but I cannot detect any back-bend in the neck 

 

can they simply stop changing the neck somehow ? The hex nut gives me the feeling of “shan’t” when I try and tighten it more 

 

[PaulWarning]

yes sanding down the bridge bar is how you usually lower the action on an acoustic but it won't effect neck relief, if it's still bowed with the truss rod fully tightened there's youtube video's where a bowed neck can be straightened, worth a go 

[Geek99]

The word on the street is that stiff neck wood on cheapies can resist a truss rod and they advocate leaving it maxed and left propped such that pressure is applied in the desired direction 

 

https://www.talkbass.com/threads/truss-rod-doesnt-seem-broken-but-doesnt-affect-the-relief-at-all.1120878/

 

@Andyjr1515 thoughts ? 

[Geek99]

I’ve done this in an attempt to push the neck to conform , strings are slack and the bottles are just above the carpet rather than sitting on it 

 

kill or cure 

 

 

 

 

[Geek99]

Still no bow back

ill try tuning it and lowering saddle and see where I end up 

[Andyjr1515]

15 hours ago, Geek99 said:

It doesn’t seem to shift much

i got the guitar with a flat neck and a slack feeling rod-nut. It’s gone tight now but I cannot detect any back-bend in the neck 

 

can they simply stop changing the neck somehow ? The hex nut gives me the feeling of “shan’t” when I try and tighten it more 

 

It's extremely difficult to tell without seeing the instrument and the problem is that it is possible to snap a rod or round the hex - and then you are pretty much stymied! 

 

That said:

The slack feeling is when there is no tension rod at all.  From the point that you can feel the nut stiffening, that is when the rod is starting to try to bend the neck.  And the nut does stiffen considerably - it surprises folks who haven't adjusted one before. 

And that leads me to a question we haven't asked - have you adjusted a trussrod before?  If so, then it's probably best to trust your instincts that if it feels too tight to turn and yes - tackle the action height from the bridge end.

 

If not, then the basics are:

- when tightening a rod, do the adjustment with the string tension off.  That is, slacken the strings before trying to adjust

- make sure that your hex key is the right size for the hex nut - 'near enough is not good enough'

- with string tension off, then from the point that you feel significant resistance of the nut, there will often be at least two quarter turns before the required 'back bow' is achieved, and sometimes more.  So if, from the point of feeling the initial resistance, the nut doesn't turn at all, then either you are not pushing hard enough...or it's stuck.  And there's the difficulty...not possible to tell from afar which it is.

- assuming that the nut, while feeling very tight, does turn.  Then - although a bit of a pain - it is important to do no more than 1/4 turn before tightening the strings to pitch again and measuring the relief.  If it's closer but still not close enough, slacken the strings and give it another 1/4 turn

 

Coalville isn't so far away from Duffield (around 3 miles north of Derby) - I'm more than happy to have a look if you want to pop across with it sometime.  PM me if you want to do that and we can sort a convenient day/time 

 

Hope this helps!    

 

Andy

[Geek99]

Yes, you helped me with a bass ski jump

i have the right sized wrench 

[Geek99]

Maybe it is stuck -it’s only a short wrench, I’ll find a longer one 

 

i got it for free, all i had to add were cheap nut, saddle and pins. If it doesn’t work out it’s not the end of the world 

[Andyjr1515]

4 hours ago, Geek99 said:

Yes, you helped me with a bass ski jump

i have the right sized wrench 

Yes - of course!  Just drop me a line if you want to pop across again anytime.