To shim or not to shim... more (or less?)

Relic · #1 12-08-2006, 07:57 AM

Was wrestling with a neck install on Fender P yesterday that ended giving me a headache. I'm trying to figure out what may be going wrong. Any input is very much appreciated.

Here's the background:
Bolting the neck on as-is resulted in the action being too low even with the bridge at max height.
I decided to adjust the truss at that point regardless and got the neck fairly straight.

Afterwards, I shimmed the neck at a point closer to the headstock to tilt it into postion. I got all the buzzing out but the action was now maxed out on the high side. (bridge wouldnt adjust any lower.)
I removed the shim and put a smaller one in - action's ok, just a little too high, but anything above the 12th fret is unplayable - the strings are far too low there to the point where you cant even play a note.
So now I'm thinking - although the neck appears to be straight using the standard checking method, is there something I'm doing wrong in the shimming? Shimming it where it's at now (closer to the headstock and away from the body) should result in the action being higher at the tongue than on the first few frets.
Do I possibly have the dreaded "tongue-rise" in the neck? Maybe the neck fell back into a bow after adjusting? I'm puzzled

vindy500 · #2 12-08-2006, 08:01 AM

sounds like you have a back bow to me

Relic · #3 12-08-2006, 08:16 AM

Quote:

Originally Posted by vindy500

sounds like you have a back bow to me

I thought of that vindy, but a back bow should pinch the strings off mid-neck rather than at the tongue I would think? It's really odd

Relic · #4 12-08-2006, 11:30 AM

Joshua and Glenn - Thanks for the very good advice, when I get home this evening I'll go for round two bearing in mind what's been suggested.

Just a clarification though - my wording was poor, I didn't intend to make it sound like I was using the truss to adjust action, what I should have specified was that when I first installed the neck, even with the action too low and the saddles actually set to their maximum height, I could see that there was too much relief,(using the strings as a straight edge) so I set it at that point to have just a slight amount. My thought process was that having a neck as straight as possible would help me be able to gauge the tilt/shimming just right.

I'm going to straight edge the sucker thoroughly tonight. That's really what I should have done 1st!
Thanks again guys.

Relic · #5 12-08-2006, 01:19 PM

Exactly - the neck is too tall, I really should have mentioned that lol. The problem seems to that, when I get the action just right via shimming , and the neck fairly straight, the bass is unplayable beyond the 12th fret. That's why I suspect tongue rise.
Well the straight edge doesnt lie, I'll check tonight.

Relic · #6 12-08-2006, 09:31 PM

two hours and three beers later... *hiccup*.. yes tongue rise + bad fret work, shimming is right on. After some fret leveling she's well on her way to perfection.
Thanks again for the input!