Can someone please educate me on neck shimming?

Against my better judgement I purchased a MIM Fender Special Run telecaster off EBay for a very reasonable price. New (2011) with tags and plastic still on the pick guard. It's cherry burst over a nice piece of ash and is drop dead gorgeous. There's a 1" ding near the output jack which doesn't bother me, but it would limit the value in a store.

Anyhow, I unpacked it yesterday and plugged it in. It played perfectly, the Tex Mex pickups sounded great, but I noticed the neck wasn't properly tightened. Fair enough I thought, the seller has probably loosened the neck bolts for shipping. So I gently tightened the neck bolts and, WTH, there's fret rattle on all strings in nearly all positions. The strings weren't even clearing the higher frets. I decided to loosen the truss rod to get some extra neck relief, but it was already backed right off. The neck looked dead straight so I measured the relief in the neck and it was at the Fender spec - 0.010" at the 8th fret. Just a very slight back bow.

I loosened the neck bolts again, about a 1/4 turn each, and there was enough play for the neck to make the correct angle with the body. She played great again. I have 8 guitars and I've never had this problem before. Is this the sort of situation that requires a neck shim? Or is there something more fundamentally wrong with the angle of the neck heel or the neck pocket? The neck feels unstable with the bolts backed off so I really need to have them tightened.

My first thought was "I need to drop this guitar off at Darwin's house".

While I had the screwdrivers out, I took off the pickguard and control plate to have a look under the hood and was amazed at what I saw. In the neck pup cavity were random balls of tape, probably used for masking at the factory then dumped in there rather than the bin. The neck pickup had a large metal staple laying across the pole pieces. God knows how that got there. The pickguard had been applied while the lacquer was not completely dry, so little spots of lacquer lifted away with the pick guard. The soldering was pretty average in places and the bridge plate doesn't appear to be grounded in any way. They're all minor things, but it's a telling reminder that the people working on these guitars are (a) really pushed for time (b) plain shoddy or (c) a combination of (a) and (b).

I'm confident it'll play great when I sort the neck out, but my MIK Tributes crap all over the MIM as far as build quality goes.

Welcome to the world of used guitars Philby! I am not sure about the Mexican neck but the American Fenders have a Bi-Flex truss rod and if you back it off and keep going it will get rid of a backbow. It is doesn't have the Bi-Flex then you will want to shim the neck on the outside two bolts and effectively raise the headstock to the body. Place the shims on the outside of the screws. Use a brass shim about 3/8 by the width of the neck. I would start with a .010 thickness and work from there. If you lived here you could bring it to my house and we would have it squared away after a couple of cold ones. Maybe someone else here knows if the MM neck is Bi-Flex. Good luck and I know this baby is fixable as long as the neck is straight. -- Darwin

Thanks Darwin. You're the Man. I'll have a cold one while I do some shimming tonight.

I'm pretty sure the owner's manual says it is a traditional truss rod, so bi-flex will not save me.

The neck is dead straight though, so I'm not too concerned there.

Where do you get brass shims? An auto repair shop? Cut some from feeler gauges?

Cheers,

Phil.

Phil, I get them at our local hardware store. They come in 4" x 10" sheets for less than $4. --Darwin

Funny, but I never ever used a brass shim. I just use very thin cardboard, about the thickness of a cereal box. Fruit Loops is nice, plus you get a nice fruity aroma.

One shim that size is usually enough, but if it needs more I double-stick tape 2 pieces together.

Will

I use layers of thin (8mil, 0.2mm) copperfoil for shimming, especially when I need a wedge to get the proper tilt (zig-zag cut to avoid sudden stepsr). Copper is soft enough to follow the surfaces exactly but it doesn't compress and provides full contact. For thicker flat shims I use maple veneer of the needed thickness. The shim should cover the whole neck pocket area to avoid uneven force (unless I need exactly that to deal with "ski-jump" or the like)

Funny, but I never ever used a brass shim. I just use very thin cardboard, about the thickness of a cereal box. Fruit Loops is nice, plus you get a nice fruity aroma.

One shim that size is usually enough, but if it needs more I double-stick tape 2 pieces together.

Will

+1 - I have used cardstock with success.

Almost all of my guitars have Micro-tilt, so I haven't needed to shim a neck in years. The last one I remember shimming was my Fender bass back in the mid-80s. I think I used a nylon guitar pick for that.

I have used aluminum foil to shim the tables on woodworking tools before. It is thin enough to make very fine adjustments, and always on hand in the kitchen when I need it.

Ken

Jeez Phil, an oily Legacy and a Tele full of rubbish! You know how to pick 'em! Hope you get it sorted. I'm pretty sure it was Jos who posted a picture of a G&L branded wooden shim in the neck pocket of his Korina Jr. Classy touch. A friend of mine has used worn out picks and old credit cards. Seems that anything will do the job.

i think darwin misunderstood what philby is saying. if you have the .010 relief, that is not a backbow, so you don't need the biflex, nor the shim. if it had a backbow (which it doesn't per the measurement) the shimming wouldn't help either, as the backbow would still be a problem. shimming is to solve the problem if the saddles are out of range for height adjustment.

Thanks for the pointers everyone. I've done some further research and found that about 50% of vintage Fenders were shimmed straight outta the factory. Leo used to use the business cards of employees that had left the company. That makes me feel more comfortable that there's nothing inherently wrong with the guitar.

Louis, I've run out of saddle height adjustment at the top end of the range. Most shimming seems to be needed for the opposite problem, where the saddles can't go any lower.

The neck has a very slight back bow, but the angle the neck makes with the body seems to be off. I've put a strip of business card at the front of the neck and the neck angle is now perfect. I intended to put something more durable in there like a guitar pick, or aluminium foil, but now it aint broke I think I'll just play the sucker.

Unless I put some Fruit Loops packet in there for some extra fruity mojo.............

Thanks for the pointers everyone. I've done some further research and found that about 50% of vintage Fenders were shimmed straight outta the factory. Leo used to use the business cards of employees that had left the company. That makes me feel more comfortable that there's nothing inherently wrong with the guitar.

Louis, I've run out of saddle height adjustment at the top end of the range. Most shimming seems to be needed for the opposite problem, where the saddles can't go any lower.

The neck has a very slight back bow, but the angle the neck makes with the body seems to be off. I've put a strip of business card at the front of the neck and the neck angle is now perfect. I intended to put something more durable in there like a guitar pick, or aluminium foil, but now it aint broke I think I'll just play the sucker.

Unless I put some Fruit Loops packet in there for some extra fruity mojo.............

if the neck has back bow, how do you have relief?

if the neck has back bow, how do you have relief?

I think I've mixed up my terminology Louis. Sorry about that. With the truss rod fully slackened off, there is a small amount of relief when the strings are tensioned. I was calling that 'back-bow'.

With the strings off the neck is close enough to dead straight.

Although the initial assessment of my MIM tele was far from glowing, I forgot to mention that it is fully shielded with shielding paint.

i.e. she's dead quiet

I hope G&L make cavity shielding an option at some point. A lot of folks probably don't realize how quiet single coils can be.

if the neck has back bow, how do you have relief?

I think I've mixed up my terminology Louis. Sorry about that. With the truss rod fully slackened off, there is a small amount of relief when the strings are tensioned. I was calling that 'back-bow'.

With the strings off the neck is close enough to dead straight.

that actually sounds perfect.