Is shiming dangerous?

[john grey]

Wood is an inconsistent, irregular material and the initial concept of the "electric guitar" was the use of vibratory elements amplified via electo-magnetic circuitry to produce a sound.
In time it was also discovered that wood had some effect of the timbre and elements of vibration amplification. yet an electric Bass is not an acoustic Bass, thus there is MUCH less emphasis on construction variables especially in modern profit-oriented manufacturing. Leo Fender DID NOT invent the electric Bass! Aspects of acoustic discovery & engineering occurred from many different sources. There really will never be an "Alpha & Omega" of working with wood to produce sound, let alone combining that with amplification.

 

[tstone]

One more quick question question, how are you supposed to tell how thick the shim should be.... (The bottom of the finger board to the bottom of the E string is about 4 mm.)

For standard Fender bass geometry, for every .010" you shim the neck at the end away from the headstock, you drop the string height at the 12th fret by .028", or roughly a 3 to 1 ratio.

 

[walterw]

For standard Fender bass geometry, for every .010" you shim the neck at the end away from the headstock, you drop the string height at the 12th fret by .028", or roughly a 3 to 1 ratio.

really? where did you get those numbers?

(sounds about right, though.)

 

[walterw]

...i had a bit of trouble getting the screws back in after taking the neck off. any suggestions on that? (mabe put some wd40 on the screws?)

oh god, no. a little candle wax is OK, though.

"trouble" getting the screws back in? were they binding up in the body?

those screws should slide through the body holes, and only thread into the neck. if they don't, they'll never tighten the body against the neck, and you'll end up with a gap under there (and an incorrect neck angle) regardless of shims.

 

[seanm]

I've found that plain old masking tape, or blue painters tape works fine. Very thin, and you can overlay it and taper it up to the end of the neck. Can be as gradual as you have time to invest doing.

I wouldn't use masking tape. Very acidic!

 

[tstone]

really? where did you get those numbers?

I did a quick layout on my CAD system.

 

[SurferJoe46]

Use playing cards. Take the Joker out of a pack and no-one will miss it.

They're made of pressed linen and they have been subjected to tons of pressure and heat to make them as hard and resilient as they are.

As a shim, they are the best material I've ever found.

 

[walterw]

playing cards do take way more abuse than just about any other "paper" product. good idea.

 

[walterw]

really? where did you get those numbers?

I did a quick layout on my CAD system.

nice!

how about the ratios for a typical fender 25.5" scale guitar?

 

[Showdown]

okay will try the soap or candle. why dont bass/guitar makers make it so that shiming isnt neccesary? just the saddle to be raised or lowered..

Older G&L and some Fenders have an adjustment screw on the body that pushes on a metal plate on the neck heel. You loosen the neck bolts and turn the screw to give it the angle you want, then tighten the neck bolts again. I have an '85 G&L L2000 and a Fender Zone with this feature.

 

[T-Bird]

Hi.

Ive been reading quite a few threads on 'shiming' and heard that shiming can create an "hump" on the neck of your bass due to the wood conforming to the tiny gap created from the shim. I was wondering has this happened to any one? and if so how severe was this so called "hump"? also if anyone has any suggestions on shiming feel free to comment. thanks.

When a hard (harder than the wood) shim isn't long enough and the neck screws are over-torqued, a hump will form. Especially on the firewood grade necks a certain manufacturer uses, at least on their export instruments.
NOT to be confused with the "ski-jump" hump which is a different matter.

You can make a tapered shim that fills the complete neck pocket (more work, but "safer" - if there's any truth to the hump scenario)...

IME/IMHO the only way to do it, I consider any other way to be just a hack-job.

Doing it that way will change the sustain characteristics and possibly tone (for better if You ask me) obviously, so that's something to be considered. One can obviusly use tapered strips lenghtwise if less than 100% contact area is the goal/requirement.

okay will try the soap or candle. why dont bass/guitar makers make it so that shiming isnt neccesary? just the saddle to be raised or lowered..

Every NT and set neck bass/guitar is done well enough to make the (impossible in that case of course) shimming un-necessary.

Regards
Sam