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Hi Guys,
I have a D18 that I am doing a neck reset, new bridge and re-fretting.

I have a question about the neck joint on this particular guitar. When I steamed it off and started cleaning the joint I noticed it had a pretty think shim in it. I know the guitar has had work done on it by someone that didn't really know what they were doing because they put the wrong size frets in. The tang on the frets were much too short and some of them were popping. The bridge and saddle had been shaved far too low to try and get the action back. I didn't see any outward signs of having had the neck removed before but with the way it was shimmed I am suspecting it had.

My question is this:

The shim that was in there was only on one side, and was .035" thick. I didn't check the neck alignment before removing the neck since I knew i would be doing it when I reset it.

When I started doing the reset I did check the alignment and the neck appeared to be off center but aligned so I started with one shim on the offending side. That brought the neck back to center and I added the next shim on the opposite side and started fitting the neck to the new angle. However it was still a bit sloppy so I had to add another shim and now have everything pretty tight and am about ready to glue the neck back on. I had to add the extra shim to the already thick side to keep the neck straight.

I have never run into a neck that has been this far off center or one with that think of a shim in it.

Is this normal for Martin? I have reset a couple of martins before but never run into this (what I would call) poor workmanship.

Should I have any concerns before gluing it back in?

Thanks,
Bob

Thanks for the reply Todd, I wasn't sure about that single fat shim and it didn't seem like something that would be done from the factory..


However.... I have an issue that I have not run into before on this same guitar and maybe you or someone can help me figure it out.

I shimmed the neck as I stated above and last night I glued it up. Prior to gluing I double checked the neck angle and the fit of the heal to the body as well as the fretboard tongue. Everything looked great, the neck was centered and everything looked very good. When I was fitting the joint I fit it to about 1/16th of an inch away from bottoming out in the dovetail. That is how I have always done it so when I clamp it it will seat nice and tight.

Well this morning when I removed the clamps I found that my once perfect joint between the heal and the body now has a gap at the bottom of the heal at the heel cap. I can just fit a .003 feeler gage at the bottom of the joint and it closes tight about 1/2 the way up the joint.

I am a bit confused since when I sanded the angle on the neck everything fit perfect. I have always been under the impression that when you clamp the neck down the dovetail pulls the heal into the body even tighter but this one seems to have pushed it out in that last 1/16th of an inch of clamping.

I re-checked the neck angle with a straight edge and I am still about 1/16 of an inch above the saddle which is exactly where It is suppose to be. The neck is perfectly centered so I can not figure out where this gap came from.

Now the perfectionist in me keeps saying I need to remove the neck and start over but I don't want to just repeat the same issue so I would like to try and figure out why the heal pulled away.

Any ideas?

Here is a pretty good shot of what I am talking about. That is a .003 feeler gage, I can not fit it in by the time I get about 1/3 of the way up the joint.

BTW, You see I have strings on and the guitar is perfectly set up, I have 1/2 of an inch between the strings and the top of the guitar in front of the bridge, action at 12th fret is 6/64th on the bass side and 4/64ths on the treble side. The guitar plays and looks beautiful... all but that darn gap....

Hey Todd, Thanks for the reply. I have done a few but this is is the first one I have had any problems with. The odd thing is it was a perfect fit prior to gluing it up. I have seen some guys clamp them from front to back but I just thought that was not really necessary but I guess I can see why they do it now... I somehow thought it wasn't necessary on a dovetail... guess I was wrong.

This is a pretty nice D 18 that I picked up for a good price and am planning on flipping so at least I don't have the pressure of a client waiting for it.

Time to fire the steamer up...

I guess you can teach old dogs new tricks...

Are you getting a tight fit on the dovetail over it's full lenght. May be you were just tight at the top with a bit of slack creeping in as the fit goes to the bottom. Do you use anything like carbon paper to check the full length of the fit or do you just try by wiggling?
Tom
Maybe I dropped into the party too late. Hope you got it worked out.

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A person who has never made a mistake has never made anything!!!

I concur with Todd and I think the reason is because of poor fitting of the joint. A joint like this is hard to fit correctly. Easy to get tight at the top and be mislead into thinking the total joint is tight while it is loose at the bottom. If this was a metal joint it would be checked with Mechanic's Blue to insure contact on the total length. With wood one has to use something to check the fit. Chalk, carbon paper,or whatever, but something. The only reason the joint pulls away at the bottom is because of poor fit.
Tom

_________________
A person who has never made a mistake has never made anything!!!

The single shim you describe is not that uncommon from the Martin factory, particularly on the older ones. In most cases, this shim will be on the treble side. I have also seen many necks, neck blocks, or bridges that were slightly off-center, but as long as the strings align properly on the fingerboard, it really doesn't matter.
I have done over 1300 neck resets, and I almost never clamp the heel against the body. The dovetail should pull it tight, simply by clamping on top of the fingerboard to the back of the guitar. There is another explanation for the heel pulling away from the body during glueup. The moisture from the glue can swell the dovetail, causing the neck heel to bow away from the body slightly. This swelling is also apparent when steaming the joint for a long period. I have seen the neck angle change dramatically due to this phenomenon.
One way to assure a strong pull against the body when clamping the neck is to slightly increase the cheek angle on the neck dovetail, meaning that the end of the dovetail (the widest part) will contact the neck block first. This can be determined with carbon paper. I use shims made of a light-colored wood (birch, maple, or holly), mainly because the marks from the carbon paper are easy to see.
If the base of the dovetail is making the strongest contact, the heel can push out from the body, particularly under heavy clamping pressure.

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John