Necks Shimmed by the Factory? WTH?

[Jarneskeg]

The shim is compensation for material, not design or workmanship.

Hi Tim. I am John Skaggs.
They need to find a way to compensate for the natural changes that can occur in wood imh. And I have a hard time believing that it changes that much from one end of the build process to the other, so often, that requiring a shim for a new build should be normal operating procedure. If it is, then maybe they are doing something wrong.
Again I am talking about instruments $500+ to $1,500. Especially over a grand, I don't think the mass production is an excuse. My experience working with other natural and unpredictable materials and managing to mass produce disposable medical products within tight tolerances makes it hard for me to accept.

 

[Jarneskeg]

There's nothing wrong with a shim in fact it shows attention to detail. Wood is not an exact material to work with, it expands and contracts.

I have a P-FSO I shimmed, I used a thick business card. When I was a kid we used to shim with matchbook covers. I imagine they're using a nice shim from the factory.

It's one of those things with bolt on necks. The material has to be suitable, the pocket and the heel have to be exact as possible, and the humidity has to be stable continuously. The only other work around is a neck through.

Valve trains on engines are shimmed, and it's shimmed to tolerance, a shim is more exact than a thread and nut.

Thanks for that comparison, because I can definitely relate.
I used one of those plastic square bread bag clips as a shim once. Had to sand it down a little, but it definitely helped.The hole in the middle went around the bass side bolt nearest the bridge.

 

[Jarneskeg]

Most if not all of them do. Some times it's just a sliver of emery cloth.
It's an in house fine adjustment, a tweak. Be glad they actually do it.

I am definitely glad they do it instead of not doing it and letting a subpar set-up out the door. My problem is that they need to do it so often.

 

[Jarneskeg]

And G&L ! Where it was first implementer. The system got a bad rep. Mostly due to over tightening the neck screws . That and the sloppy neck joints 73nder was producing at that time, with a 3 bolt attachment allowed side to side movement of the neck. Hence the over tightening in a futile attempt to keep the neck aligned.

Yeah, that was a bit of a mess.

 

[Jarneskeg]

If you really want a bass minus that pesky shim, see if you can find one of these:

View attachment 7030013
View attachment 7030014

I have been a fan of graphite necks for decades, but never had a neck thru graphite or a full composite build.

 

[Jarneskeg]

Wait til you find out that Fender has been doing this since the 50s

It was standard practice in the early decades of bolt-on guitars and basses, and I assume set necks too.

 

[Jarneskeg]

I've heard it said that a strip shim that disrupts full heel contact with the pocket can cause all kinds of weird tone and sustain and dead-note issues, because the neck and body are no longer vibrating as a unit. So if a shim is needed, it's best to use one that totally covers the neck heel, like the ones Stewmac sells. Can anyone confirm or deny this? Anything to it?

FWIW, at least 15 and maybe 20 Fenders have come my way since the mid 1970s, and I have yet to see one that had a shim.

I had heard this too. I have used a partial shim before, and while it worked, it definitely created a tiny space where the neck was not in contact with the shim or the body.
Whether this had any real impact on sustain or dead notes - I never noticed any, but I had only been playing 18mos at that time.

 

[Jarneskeg]

My point was, if you never remove the neck and you never know it’s there, what difference does it make

Yep, got it - tree falls in the forest, Schrodinger's cat, impossible barber - intellectual comic relief definitely appreciated.

 

[Jarneskeg]

Shims have nothing to do with “quality”, but has everything to do with manufacturing tolerances and expansion/contraction/variations of the wood material itself. One could ineffectively argue that manufacturing tolerances should be smaller in theory, but it just doesn’t work that way in practice. Any bolt-on guitar design is likely to use shims at some point. On my own guitars, I usually cut my wood within .003”-.006” of spec, which is barely perceptible. I have actually used shims once or twice.

But using shims is not standard operating procedure for you. If you are cutting wood within .003"-.006" of spec, I assume your intent is that the guitar will shake out without the need for shims or similar compensatory adjustments.
I would be happy to buy a shimmed instrument from a builder who I knew paid great attention to detail and is dedicated to his or her craft.

 

[Jarneskeg]

It's not a design or workmanship flaw. It's wood. You can cry about it all you want, but wood is not a perfectly stable material.

I was going to respond but all these tears I am crying over shims made it difficult to type.

 

[Jarneskeg]

Personally, I've played some US made basses at Guitar Center that were borderline unplayable they were set up so poorly. I wish more manufacturers and retailers would care enough about user experience to set them up, either with or without shims, before selling them.

I definitely agree with this. I still don't think it should be necessary as often as it is. Often to me is 1 of 10 or more.

 

[/\/\3phist0]

I had heard this too. I have used a partial shim before, and while it worked, it definitely created a tiny space where the neck was not in contact with the shim or the body.
Whether this had any real impact on sustain or dead notes - I never noticed any, but I had only been playing 18mos at that time.

when a shim I called for, bridge saddles can’t go low enough to achieve desired action I use a full pocket shim. I prefer to use the maple shims from stew Mac. They come in flat thicknesses or selected degrees of angle. There’s also plastic shims of the same type available for cheap on Amazon.

 

[Nenor]

When a shim is needed on a new instrument it's a bad design, for whatever reason. As the instrument ages the quality of woods and construction becomes apparent and a shim is an optional solution (one of several) for bottomed-out saddles.
Personally I don't like shims for the simple reason that they raise the bottom of the neck and strings higher above the body surface.
Then, you hear some boutique builders praise on how much work goes into matching the neck to the body - while on the subject of shims it is acceptable, in their view, that a(their) new instrument would benefit from an added shim. Well... make up your minds, you charge high $$ for that matching hand work you claim to be doing.

 

[Jarneskeg]

it's a surprise to those who have an extremely high expectations of their mass produced instrument.
Somehow they got the impression that their bass was PERFECT IN EVERY WAY.

I was surprised, but it bothered me, not because I thought they were perfect, but because I already knew that they weren't. I expect and have seen flaws in mass produced instruments. But, if you get lucky with your purchase, you can get a decent instrument that you can tweak and improve over time.

Then I hear this about shims and now I realize that these manufacturers that I don't trust to build a proper neck or do a proper fret job are shimming they before shipment? My thinking is that if the bass needed a shim brand new, then that neck was suspect to begin with and will most likely get worse with years of use.

 

[chris_b]

I get that you are all saying a shim isn't a bad thing, but I would hope that with CNC doing all the measuring and cutting these days there would be no need for a shim. Getting the CNC program wrong is a basic mistake that no company should be making.

 

[pcake]

Schrödinger's cat of the bass world?

shrodinger's shim...

Back in 2008, I had an Alleva Coppolo with a neck shim. It was just a thin strip of sandpaper that was glued into the neck pocket. Got it used but I’m pretty sure Jimmy did this.

one of my new, factory-boxed basses in the last two years had a sandpaper shim in the neck pocket. i can't remember which one, but my husband usually uses copper shielding tape to shim necks.

I get that you are all saying a shim isn't a bad thing, but I would hope that with CNC doing all the measuring and cutting these days there would be no need for a shim. Getting the CNC program wrong is a basic mistake that no company should be making.

but wood shrinks and swells with humidity or as it dries. you can cut something perfectly with a haas CNC mill, although wood grain alone means it won't be as perfect as metal would be. but unless you IMMEDIATELY attach the freshly cut neck and freshly cut neck pocket that were dried to the exact same humidity, the woods are going to shift. not to mention that wood glue adds moisture to the wood, and there's no reason both the neck and pocket would absorb the same amount of moisture, so no matter how perfectly the parts are cut, there's going to be some shifting. ergo, shims.

the bottom line for me - if a bass sounds great and plays great, there's a decentchance i will never know or care whether it has a shimmed neck or not. if it sounds good, feels good and everything works, it is good. at least, it my universe.

 

[chris_b]

. . . . but wood shrinks and swells with humidity or as it dries.

If the wood is drying out so much it changes the dimensions that the CNC machine cut then that is a manufacturing error. Wood should be stored until it reaches the correct moisture level, so that movement does not occur during the manufacturing process.

So either the CNC machine is off or the wood being used hasn't been dried out correctly before milling.

I know wood can swell and shrink and if you take a bass to Hawaii then back to Alaska you're looking at issues, but during the manufacturing process? It's like being sold a new car with a puncture repair.

 

[EliasA]

Easy, just build your own and show them how it should be done.

No seriously, getting into lutherie is a great thing to do if you have the time. (not speaking from personal experience as I sure don't have)

 

[TheArchitect]

Thanks for the response.

I get that it's perfectly fine, and common to use them during set up. Phobia? Not quite, but it does make me doubt the quality of instruments coming out of a factory if they have to use shims to compensate for design or workmanship flaws on a regular basis.

Sometimes the shim is part of the design, and luthiers use them as well. Those don't worry me. I am referring, for example, to a standard J-bass copy, designed to have the neck bolt directly into the pocket in a perfect fit, and the assemblers are having to add shims on the regular. That speaks to a process flaw.

I have owned Kawai, Fender, FGN, Michael Kelly, Ibanez, Squier, and Offbeat bolt-on basses. I prefer bolt-on necks specifically because they can be replaced, shimmed, modified, and removed during refrets and more serious work. I have removed the necks on all of those, except the Offbeat, and never once did I find a shim. I have had a shim added (the Kawai) but none of them were shimmed by the manufacturer.

So, like I said, not anti-shim, but assemblers having to use shims to compensate for design or workmanship flaws - that makes me wonder what else they couldn't get quite right.

I have been buying instruments for several decades now and have never seen on come from the factory with a shim. I think you are getting all lathered up over perception and heresay, and not reality.

 

[Gervais Cote]

I bought a brand new US G&L option build JB-5 (empress body) and discovered that it had been shimmed with a mess of tape. There was also some sort of note about replacement that was impossible to fully read when the tape was taken out. I eventually replaced the tape with a carved piece of a plastic Apple gift card which did a nice job.

Interestingly, two other of my US-made G&Ls have needed to be shimmed (by me, maybe they ran out of tape...) because the G-string saddle was bottomed out in order to get the relief and string height on the instrument where it needed to be. This is just one piece of the G&L QC feature set—add the little or no electrical shielding in the cavity and other goodies—but the tape was such a crap job I couldn't help but be impressed (empressed?).

[N.B. It's a really nice bass, though. And super light for a 5-string jazz-type bass.]

View attachment 7030196View attachment 7030197View attachment 7030198

Works fine for me too. I had to put that shim on my p bass as per my avatar and it now plays like a dream :

image fhoto