Neck bend.

[Zephyr]

It seems I have a conundrum.

 

The neck of the early nineties encore bass had an arch in the top 3 frets to the nut. 

Need to sought it out as had fret buzz on lowest  F first fret E string.

 

Thinking it was too tight I loosened it so that it was straight from but down to third fret. Considering all the meshing around adjusting, loosening the truss rod from the heel, bridge end, I thought not a bad effort. Until I had the pick guard on again and found I had a bow from the 3/4 fret to the 15th.

 

Now I am getting fret buzz in the middle around 5-7.

 

Anybody know what it going on?

[fleabag]

Are you sure loosened the truss rod and not tightened it ?

 

Some bass's TR's are oppossite when tightening and loosening

[Downunderwonder]

Possibly you well over did the fixing rate. When it's grossly out of adjustment it's easy to overshoot as it resettles. If I was you I would attempt to adjust the nut back half of what was put in and leave it for a day to see where it lands. 

[Zephyr]

Downunderwonder, assuming an Oz, (helping an Oz) I believe your on the right track as the neck seems to be less stressed and less fret buzz already since the adjustment. Even with the bow.
 

It is much more playable almost perfect but the for the occasional light zzz around the 7/8 fret mid strings.

 

The bass was an unknown since buying it found it’s from late 80’s/early 90’s, encore e83. Weighs a flippin ton, but I am ok with that.
 

BUT if does not resettle totally, and saddles being already at the hilt (highest) then suggestions will be appreciated as it would have a good life. 

 

But yes, will try your recommendations. 
 

and thx
 

[Downunderwonder]

Saddles max sounds like someone may have done a dodgy shim job on the neck pocket. Commonly folk put a single strip under the stub end which puts a bend into the last few inches of neck.

 

I can't tell if you are making correct assessment of the relief or where the buzzing is happening.

[Zephyr]

Woah laddy!

 

Stub end and neck pocket, geez make your pushing my geeeetar vocab.

 

Stub end/strap button end(?) but neck pocket, I get.

 

What I do not get is how is the engineering dynamics of the process that only adds pressure to the top 3/4 inches not the whole by adding the shim. 
 

Just need to know if I undo the neck and find something there what to do next.

 

And, as you are sound, well informed, have you ver straightened a neck without using a truss rod?

 

It a cool looking bass, the tones alright, and just want the action sitting just that little bit lower around the 5-12 frets.

 

 

 

 

 

[Downunderwonder]

Dunno where all the habitual tweakers got to. Stub = heel = the bridge end of the neck.

 

All I know how to do is set up and tweak from "not a million miles away" to get to "close enough for jazz".

 

All of what you're saying doesn't really compute unless it started out as royally fubared and you have done too much.

 

I really don't want to give a full blow by blow on how to do a set up if you already know.

 

First thing is make sure clockwise turning makes neck straighter. A half turn is plenty.

 

Something is way wrong when you say the saddles are up as high as they will go and it still buzzes.

[Downunderwonder]

When you started out all that was obviously wrong was a buzz coming from the low F fret? Are you absolutely sure about that?

 

If the only way to cure it was slack off the truss rod so far it banana'd then I think there's a problem that isn't truss rod related.

 

But I am far from convinced you correctly ID'd the buzz in the first place. Most people would call it the first fret buzzing on low E if that's what it was.

 

I think you need to ignore that buzz and set it up so the rest of it plays nicely. Then figure out exactly what's wrong. Something tells me it's not the setup if it's otherwise fine but buzzing on the first fret open E. Boogered nut slot, high fret, twisted neck???

 

Again, you want to be certain of that and then you probably need to go bother a luthier.

[tauzero]

A capo is an almost indispensable device to help with setup. A set of feeler gauges will also help.

 

Put the capo at the first fret and then push the E string down around the neck pickup, ie. beyond the last fret. Then check the height of the string at the 7th fret. Depending on your feeler gauges, it should be somewhere round 8-14 thou if you're primitive, or .2 to .35mm if you're using proper units. If it's a lot bigger, slacken tighten the truss rod. You can probably guess what to do if it's a lot smaller. Leave it all to settle. Look along the neck and see if you've got a pretty uniform curve.

Edited November 26, 2022 by tauzero
Directional confusion

[Andyjr1515]

On 22/11/2022 at 18:36, Zephyr said:

What I do not get is how is the engineering dynamics of the process that only adds pressure to the top 3/4 inches not the whole by adding the shim. 
 

Just need to know if I undo the neck and find something there what to do next.

 

And, as you are sound, well informed, have you ver straightened a neck without using a truss rod?

Hi @Zephyr

 

You are right to be a bit confused - because there is a lot of confusion generally in the guitar and bass worlds about truss rods and shims.

 

So - a quick explanation.

 

Truss rod

Its purpose is to make the neck straight.  Period.

 

The string tension, when fully tuned up, tries to bend the neck like an archery bow (picture courtesy of Guitarless.com) :

 

- The trussrod's job is to bend the neck the opposite way to end up with a completely straight neck.

 

- Yes - the trussrod adjustment affects the action height - but that is not its job.

 

 

Shims/Neck angle

 

If your neck is straight, when under full string tension, and the action is too high or too low for the saddle height adjustment to be able to compensate, then - for a bolt on neck - it is the neck angle that needs to be adjusted.  And a shim in the neck pocket is what is usually used to achieve that. 

 

I always find this the most useful pic to explain exactly what is going on (Not my diagram.  It is used quite often by different folks so I don't know who to thank) :

 

Using a shim in the neck pocket is nothing at all to do with bending the neck at the upper frets.  Trust me - the neck is never going to bend there from a shim (so yes. your question was quite right)

 

If your action is too high, then you put a shim at the very back of the neck pocket which then lifts the back of the neck and tilts the whole neck down ('down' from the perspective of the above pictures).  This lowers the action.   Ref the above, Pic 2 is where you are starting from with too high an action; Pic 3 is with a shim at the back of the pocket; Pic 4 is if the shim is too thick and now the action is too low and the strings are pressing against the fretboard)

 

If your action is too low, then the shim goes at the front of the pocket, which tilts the neck up. 

 

Usually, it needs no more than the thickness of a credit card and often less.  Any material can be used as long as it won't crush (and so cardboard is no good; a slice off a business card is OK; a slice of old credit/store card might be a bit thick but is ideal as a material).

 

 

 

 

Here's a shim that I found, under quite a fancy bass I am working on, when I took the neck off.  It will have been put here to lower the action enough for the saddle adjustment to be able to do the fine tuning.  It is around 1mm thick and will tilt the neck downwards, which lowers the action. :

 

 

 

If the action was too low, then a shim would be put here:

 

 

So, back to yours:

- You want to get the neck as straight as you can to start off with.  Truss rod adjusts this.  Only measure when the neck is on, the strings are on and tuned up to pitch.

- As mentioned above, the simplest way of checking is:  Hold the G down at the 1st fret and the 16th fret.  At the mid point (7th/8th fret) there should be a just perceptible gap between the string and the fret.  If it is hard down on the 7th or 8th fret, then the truss rod is too tight and creating a back bow and needs loosening.  If there is a gap, but it is anywhere more than, say, the thickness of a business card, then there is still too much bow in the neck and the trussrod needs tightening a touch

 

Once the neck is straight under string tension, you can then look at the action height.  If you can get a decent action with the saddle adjustment, then simply do that.  But, if even at the top or bottom of the adjustment range of the saddles the action is too high or too low:

- lower or raise the saddles to the mid point of their adjustment range

- if the action is too low, try a shim in the front of the neck pocket

- if the action is too high, try a shim at the back of the neck pocket

 

 

 

 

   

 

 

 

 

 

Edited November 26, 2022 by Andyjr1515

[Zephyr]

Wow!!

 

Thank you for the extensive explanation. It’s given me an incredible insight into the whole neck set up an issues.

 

brilliant… thanks!