Out the factory neck shims: Are they common?

[Beer of the Bass]

I suspect that the shim has always been considered to be part of the factory adjustment procedure in bolt-on basses. If the pocket is designed to give the correct neck angle and elevation with a small shim in place, there is scope to adjust the angle in both directions (either by using a larger shim or removing the shim) to correct for manufacturing tolerances. If it was designed for the perfect angle without a shim, adjustment would only be possible in one direction and any instruments that needed to be adjusted for less neck angle would have to be rejected. Viewed this way, it seems like a smart bit of design for production line instruments.

[uncle psychosis]

[quote name='Beer of the Bass' timestamp='1378823271' post='2205123']
I suspect that the shim has always been considered to be part of the factory adjustment procedure in bolt-on basses. If the pocket is designed to give the correct neck angle and elevation with a small shim in place, there is scope to adjust the angle in both directions (either by using a larger shim or removing the shim) to correct for manufacturing tolerances. If it was designed for the perfect angle without a shim, adjustment would only be possible in one direction and any instruments that needed to be adjusted for less neck angle would have to be rejected. Viewed this way, it seems like a smart bit of design for production line instruments.
[/quote]

^^ this.

[BOD2]

[quote name='stingrayPete1977' timestamp='1378820487' post='2205065']
I'm probably not explaining it very well, hopefully someone else can do a better job?
[/quote]

Lots of info and some discussion here [url="http://basschat.co.uk/topic/49897-how-to-shim-a-neck/"]http://basschat.co.uk/topic/49897-how-to-shim-a-neck/[/url]

In the middle of the topic there is a diagram (by BigRedX coincidentally) that shows what neck shimming actually does.

[Grand Wazoo]

[quote name='stingrayPete1977' timestamp='1378762360' post='2204512']
Most stingrays have a plastic shim fitted as standard I think?
[/quote]

ALL of the EBMM have shims, I had 6 different ones and they all came with shims even the most expensive 25th Anniversary model before it became the Reflex

[BigRedX]

In fact I've just revisited that diagram and the only way that I can make the shimmed neck angle do something that can't be also be done by raising or lowering the bridge saddles is if they run out of travel before the desired action is reached.

There is always a triangle formed by the string, the plane of the fingerboard and the height of the bridge (relative to where the plane of the fingerboard intersects it. The action is only changed by raising or lowering the bridge relative to the plane of the fingerboard. All shimming the neck does is change the orientation of this triangle with respect to the body.

Edited September 10, 2013 by BigRedX

[stingrayPete1977]

Forget perfect world necks and truss rods, the post below BRX's diagrams sums it up best......
[quote name='Kongo' timestamp='1243875872' post='503126']
Shimming the end of the neck pocket also makes the actiob even throughout so even if you like your current action but would like it the same all along the fretboard you can shim for that too.
[/quote]

Raising a neck within the pocket to compensate for a bridge that has its saddles bottomed out is nothing like adding a tilt via a shim or the microtilt adjuster.

[BigRedX]

[quote name='stingrayPete1977' timestamp='1378830328' post='2205269']
Forget perfect world necks and truss rods, the post below BRX's diagrams sums it up best......
[/quote]

Really? I found that statement completely incomprehensible.


[quote name='stingrayPete1977' timestamp='1378830328' post='2205269']
Raising a neck within the pocket to compensate for a bridge that has its saddles bottomed out is nothing like adding a tilt via a shim or the microtilt adjuster.
[/quote]

The only difference between the two is that using a shim or a tilt adjuster changes the angle of the neck in relation to the body. It does not fix an action problem unless the bridge saddles have run out of travel.

[stingrayPete1977]

You set the bass up, saddles are in the middle of their travel no problems, action nice and low at the 12th fret and the truss rod is holding the neck totally flat with no releif at all, you play it and the fretted notes are buzzing and rattling all over the place, what can you do?

Add some releif until the rattles go, but now the action is quite high around the middle of neck even with the saddles lowered right down and the action really low at the 12th fret.

Raise the action and leave the truss rod alone, that wont help will it because you already had a good action you were happy with so now its too high.

Pop a shim in the heel to tilt the neck back and let a bit of tension off the truss rod for a comprimise between the two, set the action at the 12th fret and enjoy a rattle free bass

[Ghost_Bass]

BRX's diagrams are perfect, there is only one last diagram missing, the case where you get a high action and simply lower the saddle to get a low and even action across the fretboard.

I think the diagrams are self-explanatory and are the best way to explain how the shim works and they should be rearranged by priority in a step-by-step and sticked on the forum or wiky.

Order of diagrams, IMO:

1- High action? Y - Check neck bow!
2- Still high action? Y - lower bridge saddles!
3- Reached bottom of saddle travel and high action? Y - apply shim

But all of this is off-topic. The question is why is a shim needed on a factory bass?

I can see the need for one when replacing the bridge for a taller one that will run out of travell before lowering the action enough but shouldn't the factories produce basses with a tolerance that fits around the middle of the traveling point of their own saddles without need for a shim? They already know the height of the bridge they are using and all the parts dimentions...

Here's my own explanation to this, take it with a pinch of salt:

The finish of a body affect the bridge's height (satin or gloss - gloss adds more thickness to the body raising the bridge a bit).

Manufacturers could have two programs with different heights on the neck pocket to use with either gloss or satin finish but they ignore this in order to knock out more units per hour on their CNC's. They would have to select wich bodys were going to recieve thick finish and wich ones wouldn't...
That's the real reason for factory applied shims, they want to sell more and faster. This could be acceptable on low cost basses but certainly not on the top ones!

Cheers

[gjones]

[quote name='stingrayPete1977' timestamp='1378817832' post='2205004']
It's not at all, you can't adjust the whole length of the neck. I'm certain I'm right on this one BRX.
[/quote]

You are. I used to try my best to get a decent set up by tweaking the truss rod and fiddling with the bridge but it never worked. As soon as I fitted the shim it made it possible to get a decent action.

[Dingus]

I have heard some people ( well , one person , to be precise, and other folks seemed to agree with him ) claim to be able hear the difference between a wood shim and a card shim under a bass neck . Needless to say , I am sceptical about that claim . Lots of basses have shims , including some very expensive ones . If the bass plays well , sounds great and has no reliability issues as a result of being shimmed , why worry ? Yes in an ideal wiorld , all basses would play perfectly without them , but expect to pay substantially more for the same bass without a shim in that ideal world . Precision manufacturing costs money , and the reality is that bass makers at nearly all price points need to keep costs down to avoid pricing themselves out of the market .

[Ghost_Bass]

[quote name='stingrayPete1977' timestamp='1378832024' post='2205298']
(...)

[b]1:
Add some releif until the rattles go, but now the action is quite high around the middle of neck even with the saddles lowered right down and the action really low at the 12th fret.[/b]

(...)

[b]2:
Pop a shim in the heel to tilt the neck back and let a bit of tension off the truss rod for a comprimise between the two, set the action at the 12th fret and enjoy a rattle free bass [/b]
[/quote]

I'm sorry to mess with your quote Pete but aren't number one and two virtually the same thing? The release you need to aplly to the shimmed neck in order to "enjoy a rattle free bass" is the same you need tp aplly to a unshimmed (does this work exist?) neck to get the same result. Only difference between both methods is to change the saddle height in oreder to achieve the same effect! Simple geometry!


For all that is worth i want to add that the best (lowest) action i ever had was on my parted Singray5, factory setup, had a bit of fretbuzz but not audible through the amp, played like butter

[Fionn]

The space in the neck pocket which is caused by a shim means that full contact is lost at a critical point in the structure of the instrument. As a result the resonance is effected, sustain is lost. The acoustic qualities of the instrument are compromised.

A new instrument that needs a neck shim is either porly designed, or poorly made (or both) in my opinion. Aye, that includes the holy grail that is Fender. Och, maybe such technical imperfections are crucial to the wholeFender vibe.

[Beer of the Bass]

[quote name='Fionn' timestamp='1378833545' post='2205337']
The space in the neck pocket which is caused by a shim means that full contact is lost at a critical point in the structure of the instrument. As a result the resonance is effected, sustain is lost. The acoustic qualities of the instrument are compromised.

A new instrument that needs a neck shim is either porly designed, or poorly made (or both) in my opinion. Aye, that includes the holy grail that is Fender. Och, maybe such technical imperfections are crucial to the wholeFender vibe.
[/quote]
Although I've never heard any difference when adding a shim to an instrument. Perhaps I have cloth ears, but then there are plenty of other subtle differences I do pick up on. I think that unless the joint has been chalk-fitted by an extremely skilled woodworker (as is done with glued joints in acoustic instruments), there's not going to be full contact anyway.

[stingrayPete1977]

[quote name='Ghost_Bass' timestamp='1378832946' post='2205322']
I'm sorry to mess with your quote Pete but aren't number one and two virtually the same thing? The release you need to aplly to the shimmed neck in order to "enjoy a rattle free bass" is the same you need tp aplly to a unshimmed (does this work exist?) neck to get the same result. Only difference between both methods is to change the saddle height in oreder to achieve the same effect! Simple geometry!


For all that is worth i want to add that the best (lowest) action i ever had was on my parted Singray5, factory setup, had a bit of fretbuzz but not audible through the amp, played like butter
[/quote]

The ideas with geometry and straight lines does not work because the neck is not straight only the strings are, what you are doing in effect is introducing a slight (so slight most players me included dont need it) dip around the 15-17th frets by offering the neck at a slightly tilted angle to where it was before.

[Fionn]

[quote name='Beer of the Bass' timestamp='1378833972' post='2205343']
I think that unless the joint has been chalk-fitted by an extremely skilled woodworker (as is done with glued joints in acoustic instruments), there's not going to be full contact anyway.
[/quote]

Full contact makes a difference, as in the case of neck-through-body basses which have notably better sustain. Both my basses are neck-through-body. I like the acoustic resonance afforded by that method of construction.

Bolt-on, less so. Shimed bolt-on .... even less so.

Folk will buy basses with shimmed necks then add expensive high-mass bridges and the like to improve the resonance. Why not just buy a bass which has been correctly made in the first place?

[Mr. Foxen]

[quote name='MisterFingers' timestamp='1378822556' post='2205113']
truss rod adjustment couldn't pull the neck back any more
[/quote]

Truss rod is unrelated to the shim/bridge thing. Truss is there to ensure the right amount of arc relief in the neck, overall action should be adjusted elsewhere, relief just determines how consistent that action is along the neck.

[Beer of the Bass]

[quote name='Fionn' timestamp='1378834542' post='2205355']
Full contact makes a difference, as in the case of neck-through-body basses which have notably better sustain. Both my basses are neck-through-body. I like the acoustic resonance afforded by that method of construction.

Bolt-on, less so. Shimed bolt-on .... even less so.

Folk will buy basses with shimmed necks then add expensive high-mass bridges and the like to improve the resonance. Why not just buy a bass which has been correctly made in the first place?
[/quote]
So long as the playability aspects are sorted, I don't understand the notion of correct and incorrect in instruments. If a bolt-on neck as typically executed is less effectively coupled to the body than a through-neck resulting in a different character to the sound, I don't see that as being wrong or incorrect. It's just the nature of that instrument. Personally I find that many of the "improved" bass designs with through necks, no dead spots, long sustain and perfectly even response don't interest me at all.

Edited September 10, 2013 by Beer of the Bass

[MisterFingers]

[quote name='Mr. Foxen' timestamp='1378834594' post='2205356']
Truss rod is unrelated to the shim/bridge thing. Truss is there to ensure the right amount of arc relief in the neck, overall action should be adjusted elsewhere, relief just determines how consistent that action is along the neck.
[/quote]

I understand, but surely something like string tension affects that arc-and the consequence is a higher string action if (for example) you use a heavier gauge. So in that case you would adjust the truss rod [i]and[/i] lower the action at the bridge to compensate. The problem comes when the saddles are at their lowest and the overall action is still too high - and then you would have to insert shims.(?)
What's the general opinion on non-wood or paper shims? metal? perspex etc.?

[gjones]

[quote name='MisterFingers' timestamp='1378836260' post='2205383']
I understand, but surely something like string tension affects that arc-and the consequence is a higher string action if (for example) you use a heavier gauge. So in that case you would adjust the truss rod [i]and[/i] lower the action at the bridge to compensate. The problem comes when the saddles are at their lowest and the overall action is still too high - and then you would have to insert shims.(?)
What's the general opinion on non-wood or paper shims? metal? perspex etc.?
[/quote]

I used a sliver of an old Morrisons loyalty card wrapped in gaffa tape. Didn't make any difference to the sound.

Edited September 10, 2013 by gjones

[Fionn]

[quote name='Beer of the Bass' timestamp='1378835237' post='2205368']
So long as the playability aspects are sorted, I don't understand the notion of correct and incorrect in instruments. If a bolt-on neck as typically executed is less effectively coupled to the body than a through-neck resulting in a different character to the sound, I don't see that as being wrong or incorrect. It's just the nature of that instrument. Personally I find that many of the "improved" bass designs with through necks, no dead spots, long sustain and perfectly even response don't interest me at all.
[/quote]

Fair enough man. They are all horses for courses at the end of the day. Each to their own, and all that

[Mr. Foxen]

[quote name='MisterFingers' timestamp='1378836260' post='2205383']
I understand, but surely something like string tension affects that arc-and the consequence is a higher string action if (for example) you use a heavier gauge. So in that case you would adjust the truss rod [i]and[/i] lower the action at the bridge to compensate.
[/quote]

Truss rod needs to compensate for string tension change. Action needs to be adjusted as a separate thing because the lower string deflection means you can set it lower. Should not use the truss rod to compensate for the action being set wrong elsewhere, two independent factors in playability of an instrument.

[MisterFingers]

Got you, cheers.

[stingrayPete1977]

OK here is my terrible drawing of how I have acheived a better overall action with shims or microtilts (pre EB Rays), I have tried to accentuate the angles so we are talking tiny amounts in reality, for me this is only applicable for basses where the neck will only straighten from a certain point before giving a back bow.

[URL=http://s997.photobucket.com/user/stingraypete/media/20130910_190855_zps5b25b63b.jpg.html][IMG]http://i997.photobucket.com/albums/af100/stingraypete/20130910_190855_zps5b25b63b.jpg[/IMG][/URL]

[BigRedX]

It doesn't matter that the neck is not a straight line. The dip never moves in relation to the strings except up or down as determined by the bridge.

If your theory was correct then it would be impossible to get a really low action on either a set neck or through-neck bass. But this is patently not the case.