I've recently finished a bass kit. I have determined i need to shim the neck (neck is straight, bridge is as low as it go and strings still too high). A coupla .032" washers would do the trick but I have read this is not a good idea as "over time" that end will distort the neck and raise the frets at the treble end. How long is "over time"? 1 year? 5 years? 6 months?
Really just for my curiosity as I have already ordered some proper shims.
Thanks
I'm assuming this is a bolt-on neck.
I think this is really in urban myth territory. I've known people who've had guitars with shimmed necks where that were done over 40 years ago. I've shimmed a lot of necks in my time and I've never had a problem.
The pocket end of the neck (including the fretboard) is normally the thickest part of the neck and its also the squarest. So it's definitely the strongest part of the neck. So why would that warp and not the thinner contoured part of the neck that's probably got 2/3 the material of the heel in cross-section. Not forgetting the nut end has the most leverage force applied through string tension?
I'm not one to say that it could never happen, but you'd probably need a whole combination of factors such as repeated big temperature swings and large humidity changes, spread over a long period of time before it's ever likely to occur. If it does, you're probably also looking at wood that has inherent weaknesses in it (as not all necks are made from the ideal combination of quarter-sawn, very straight grained wood). In many instances you'd probably find those frets would have become loose anyway, but because the neck has been shimmed, people then think that's the primary reason. The fact that the fret slots are closer together at the treble end may possibly have something to do with it. But if it happens, it's rare.
I personally wouldn't use metal washers as shims. I feel metal is too hard. The luthier books normally recommend wood veneer or hard plastic. I normally use a strip of thin hardwood veneer, about 10mm wide, across the full width of the pocket. Thin veneer is somewhere between 0.6mm-0.8mm thick. If I need something a bit thicker I'll stick two strips together.
Thanks. You seem to be everywhere and I am glad.
I thought about strips of credit card. Good to know about choosing something besides metal..
I normally view the forum on my PC and get the full list of forums up, and it they indicates those with new posts, I read almost all those.
You can make your own full length angled shim if you want to, it's not too hard. But for bolt-on necks, as opposed to glued-in, I don't think it gives any real benefit.
Most of the forces on the neck joint are on the two front (neck end of the pocket) screws and where the neck meets the end of the pocket. It's the end of the pocket that takes most of the tension force. The upward component of force derived from the strings being at a slight angle to the fretboard is actually quite small in comparison.
And of course you have *sonically* tested side by side singe end shim vs full length shim on the instruments yes? Not that I'd ever play devil's advocate, oh no, not me..... <gryn>Originally Posted by Simon Barden
No I haven't. But I have obviously played several guitars without the with the neck shim in, and I certainly couldn't tell any before and after difference (a full length neck shim should sit somewhere between the two). I won't say there isn't any change at all, as I have to rely on my memory, and I haven't done recordings. But if there is, there's not enough difference to make a noticeable change to the way the guitar sounds when listened for. Even if there was a very small detrimental difference, for me that would be far outweighed by the increase in playability gained by fitting the shim.
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