Shim for changing the neck angle slightly.......

[Chewie]

Hello Groovers,

 

Anybody know a sensible way to do this without buying the correct things from stewmac and others?

 

Probably not but I'd thought I'd put it to the panel first.

 

Thank you in advance

[Chewie]

I've just seen another thread on here using a business card............

 

Might try that first.

 

Can't hurt.

 

 

[Reggaebass]

Just now, Chewie said:

I've just seen another thread on here using a business card............

 

Might try that first.

 

Can't hurt.

 

 

Was just going to suggest that, it’s always worked for me 

[PaulThePlug]

As a temp or range finder...

Full Neck Pocket Angle Shim is preferable... otherwise you might get a 'Ski Jump' to the neck at the pocket.

[Baloney Balderdash]

30 minutes ago, PaulThePlug said:

As a temp or range finder...

Full Neck Pocket Angle Shim is preferable... otherwise you might get a 'Ski Jump' to the neck at the pocket.

It's a myth.

 

Neck might develop a "Ski Jump", there is always that risk, but it is for certain not because of a part shim.

[PaulThePlug]

Oakley Dokley... 🫡

https://hazeguitars.com/blog/neck-shimming-and-ski-jumps-the-latest-research#:~:text=What causes a ski jump,this problem much more likely.

 

[MoonBassAlpha]

I've never seen a part shim cause a problem either.

[Baloney Balderdash]

On 17/01/2024 at 20:33, PaulThePlug said:

Oakley Dokley... 🫡

https://hazeguitars.com/blog/neck-shimming-and-ski-jumps-the-latest-research#:~:text=What causes a ski jump,this problem much more likely.

 

I strongly question the scientific validity of that blog.

 

This for example proves absolutely nothing:

Quote

And, in my experience, poor neck shimming practice can make this problem much more likely.

 

So where in the blog is the statistical data to support that, and more specifically data where that has also actually been proven to be the actual cause?

 

If this was true it would look bad for wooden furniture, and we wouldn't have 100's of years wooden furniture pretty much holding the same shape in which they were made, wooden tables without bend plates and legs, or wooden chairs without bend seats and legs.

 

Even less is a piece of cardboard going to course something like that.

 

Calling something research doesn't automatically make it scientifically valid, or even just at least real research. 

 

Edited January 20 by Baloney Balderdash

[Andyjr1515]

Depending on the thickness I need, I just use a slice of out-of-date credit card (usually that's as thick as you would usually ever need) or thin sheet plastic or other non-crushable material I come across from time to time and snaffle it to keep in my bits box.   

 

I also am not convinced by the ski-jump argument. 

[neepheid]

I've used wood veneer as a shim before.  It's about 0.6mm thick IIRC.  Also toneshim!  Lovely bit of walnut in there, will totally change the tone of the bass, can't you hear it?

 

[Andyjr1515]

11 minutes ago, neepheid said:

I've used wood veneer as a shim before.  It's about 0.6mm thick IIRC.  Also toneshim!  Lovely bit of walnut in there, will totally change the tone of the bass, can't you hear it?

 

Yes - veneer's good

[Downunderwonder]

Should get nil ski jump effect if your bridge end narrow shim straddles the screws and a half thickness shim at the other end likewise.

 

Supporting nut end of neck on the last of the pocket while holding the other aloft on the shim definitely has a propensity to bend the neck between the held flat zone at the front of the pocket and the lifted zone at the back. If you only tighten the front screws to the point the neck touches down on the pocket then there is no great bending but who does that?

[Andyjr1515]

Coincidentally, last night I took this neck off.  And that (it is veneer) is glued on and dated & monikered by the maker

 

Yup - recognise the laminations?

 

The date, if you can't read it, is 1.9.79 

 

 

As the saying goes, 'If it's good enough for Wal...'

 

[Chewie]

5 hours ago, Andyjr1515 said:

Coincidentally, last night I took this neck off.  And that (it is veneer) is glued on and dated & monikered by the maker

 

Yup - recognise the laminations?

 

The date, if you can't read it, is 1.9.79 

 

 

As the saying goes, 'If it's good enough for Wal...'

 

That’s certainly an endorsement….  Thanks for this……!

[Downunderwonder]

If you tighten the screws beyond snug with that arrangement there is bending applied to the end of the neck. It's physics that cannot be denied.

 

Another way of looking at it is all the force applied by the rear screws (and some) has a balancing force coming back from the shim. That is a force couple applying bending.

 

You can see where the Wal neck has had good contact with the body pocket. Not much of it. The Wal neck may well be made of superior timbers and the screws only tensioned enough to hold the neck on and no more. I assume there has been no ski jumping but it might pay to have a good look!

 

Back to the force couple. There is an equal and opposite couple between the sum of the body pushing back against the neck on the other side of the rear screws and the rear screws. Otherwise the neck would be rotating away from the shim. That couple is bending the neck between where it touches and the rear screws.

[Andyjr1515]

Why I like this forum - indeed it is my favourite of any of the forums I've ever used - is that we can debate stuff properly. 

 

And there's some great stuff above.

 

I thought that the article that @PaulThePlug posted was informed and logical.  But I'm not convinced about the article writer's conclusions that, essentially, 'simple shims are a terrible thing'.  My take on the writer's conclusions:

 

- Interestingly, the article writer dismisses the adverse tone impact of the simple shim.  I don't.  I actually think (and find) on a bolt-on, the firmness and completeness of the neck joint does impact the tone.  Not a lot, but tangibly so.  And you can see on the Wal photo how much area is not in contact at all! (the dark smudges are from the black paint of the body.  I checked with the owner, by the way - it was bought from new and the neck has never been off before).  But that impact is small and, to many of us, would not be noticeable

- I agree with the article writer's, and @Downunderwonder 's view of the physics that says that - as timber does bend and form over time - there is a possibility of creating a set curve in the heel area.  But I think that the aspect ratio is such that the force to do that would need to be quite high - and the two things more likely to happen first with that amount of tightening are:

                              -the neck screw threads starting to fail

                              - the shim starting to crush the neck pocket in that area and sink into the pocket floor. 

Interestingly, there is evidence of some slight sinkage of the shim into the Wal neck pocket, but still leaving a decent amount of effective shimming for the neck angle needs.  There is no ski-slope.

 

So my conclusions are slightly different to the article writer's.  They are that:

 

- An incorrect neck angle is BAD  

- A simple shim is OK  

- An accurate tapered shim is BETTER  

 

 

Two extras to keep the debate going:

Interestingly, later Wals (or maybe upper end ones?)  have a glued-on tapered shim - some partial length like this below, some full length.  This is one I worked on a while back:

 

 

The other is that - as many of you know, almost all of my builds, electric or bass, are through-necks.  Ah, problem solved!

 

Nope

 

I have to create a fall-away in every one of my builds in the frets or fretboard from the neck body joint to the heel end.  I have some thoughts why that is - and I think it's related

 

Cue music:    DUM DER UM DUM  DERRRRRRRRRR

 

 

 

 

 

 

   

 

 

[Chewie]

Just looking at basses for when I win the lottery...............

 

Saw this.........

 

https://www.andybaxterbass.com/collections/fender-jazz-bass/products/1962-fender-jazz-bass-olympic-white-slab-board

 

 

[Chewie]

Just now, Chewie said:

Just looking at basses for when I win the lottery...............

 

Saw this.........

 

https://www.andybaxterbass.com/collections/fender-jazz-bass/products/1962-fender-jazz-bass-olympic-white-slab-board

 

 

Sorry guys........

 

I mean this...........

 

I wonder what material that is...........

 

Perhaps I'll message him for the sake of research.....

[Chewie]

And again........

 

 

[Geek99]

You can find copper neck shims in a pack of various thicknesses on eBay https://www.ebay.co.uk/itm/185779208770?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=q7sruqa8QEW&sssrc=4429486&ssuid=bgbetJqEQOS&var=&widget_ver=artemis&media=COPY

Edited January 21 by Geek99

[Downunderwonder]

There is another form of timber deflection under flexion aside from bending. It is plastic. You know it as sag.

 

 

[fretmeister]

I use a bit of sandpaper as it helps grip in the pocket.

 

I have no idea if that works though!  

[Pea Turgh]

I bought some wooden full-length wedge-types off eBay.  Will let you know how I get on when I fit them (estimated completion date: some time late Feb).

[NickA]

On 20/01/2024 at 09:03, Andyjr1515 said:

As the saying goes, 'If it's good enough for Wal...'

 

My one of those actually had a full tapered shim ... I took it off and replaced it with a bit of sanded down lolly stick.  I may have knocked a few £k off it's value, but it plays better and Andyjrr checked it out at a bass bash and declared it just fine.  So yeh.

 

For all people swoon about Wals, Wal & Pete knocked them out apace back in the day and they're usually a bit wonky.... still great basses tho.

 

One day I'll get a new, and correctly angled, full shim fitted.

[Dan Dare]

On 19/01/2024 at 11:08, neepheid said:

I've used wood veneer as a shim before.  It's about 0.6mm thick IIRC.  Also toneshim!  Lovely bit of walnut in there, will totally change the tone of the bass, can't you hear it?

 

That additional air chamber created by the shim must have an effect, too 😁