Official Luthiers Forum!

I am working on a 1957 Harmony H65 archtop trying to set and reglue the dovetail in the neck joint.
I have it cleaned very well in the two joint surfaces but the fit is not adequate. I need to shim it to get a good fit. There is a slight wobble when I dry fit the neck to the body. I used glossy paper from People magazing as a shim without glue and it snugs things up nicely. I did this as a test.

What can I use as a permanent shim to glue the neck to the body? Do they make wood that thin?

Sure they make wood that thin and if they don't that's were we come it. After all wood does grow on trees...

It's standard fare to have to rebuild a dovetail to a degree to reset a neck. This involves often gluing wood shims onto the the dovetail and then refitting, noting where there is a conflict (often using chalk), paring away in these area with a chisel, and trial fitting again repeating the process until the neck angle is correct including side to side and the dovetail has a snug fit when it's in place. That was a one sentence view of fitting a dovetail...

It's a complicated process if you are new to this and not something that I believe can be learned from someone telling you how they do it. Instead understanding the process, neck angles, how to use a dovetail chisel properly, grain orientation for shims, what materials work best for shims, use of "serviceable" glues and why, and some fretting basics as well since frets should be dressed after resetting a neck are important considerations. Experience is very helpful here too so is practicing on a beater with a proper dovetail.

If this is your first dovetail reset I'd look for a tutorial on the web to help you. It is one of the more complicated operations that Luthiers do and often benefits from lots of experience. Not sure that it can be properly explained in the one dimension of a forum but instead you would really benefit from seeing it done in person.

Thanks. Ive read and seen tutorials where a chisel is used to add shims. That looked a bit risky for me. I am not working right now so I cant buy tools. This job may have to be done by a luthier so I may have to wait a few months.
I don't think my 1st dovetail attempt using a chisel should be done on a 60 year old guitar. However if I can get a snug fit using the existing surfaces and a super thin shim I may attempt the regluing job.
One time I think I even saw thin wood paper in cigar box packing. I am at present studying how much surface to surface area I have and is it enough. This neck had been reglued before very crudely using the wrong type glue over a poorly cleaned/prepped surface.

I have been unable to find a tutorial where the shim was wood paper. The ones I watched used shims that may be more accurately described as splints much thicker than paper.

At present i'm looking for tutorials that precisely match my abilities but haven't found any.
I stuck at the moment until something changes.

A long strip of veneer, clamped at both ends can be hand sanded to a very thin veneer. I am assuming that you have very limited tools and skills. Glue some sandpaper to a block of wood and go at it.

Sounds like a plane shaving or two is in order.

_________________
Jim Watts
http://jameswattsguitars.com

I doubt I could make a shim the thickness of glossy magazine paper yet that is what I need.
I'm also unable to determine how much surface area I have existing. Somebody tried to glue this dovetail before and the attempt failed. Why? Do I need more surface contact area? It's hard to tell what is going on inside a dove joint. It's hard to tell when you are at the point where you can successfully apply the glue and clamp the joint. I'm at a point prior to that.
At this time I seem to lack the knowledge, tools and supplies. I'll keep studying though. I spend an hour a day studying this guitar. I notice that things happen when my knowledge catches up to what I want done to this guitar. It is slow going at the moment.

Rub chalk on the male part of the dovetail and stick it together. That will show you how much contact you have.
Most folks that redo dovetails make larger shims and keep chalking and sanding till it fits. See if you can find the dovetail videos from John Hall. He shows you how to do it. Think they are on Yootoob...
If you can't figure it out, take it to a repair person.

If you can't make a shim that is thin enough, pare down the dovetail pin until you can make a shim that is a little thicker and easier to make.

Alex

_________________
"Indecision is the key to flexibility" .... Bumper sticker

I'm thinking that is what may need to be done but being outta work I may have to wait till I can splurge on a good chisel.
I'd like to add some shim at the back of the neck but the tutorial I saw had to remove the fretboard to gain top access for that. I'm not removing the fretboard.

No, you don't add a shim to back of neck. That defeats the purpose of a dovetail joint. The gap is there to enable you to get the joint apart should you need to. You don't need a chisel either.
All you need is this:

https://www.youtube.com/watch?v=L3YJh9OT4mw

There are 4-5 vidios total.

Well it kind of died at the end on me. But it was very good what I saw. I have built 4 dovetail joints. However,I've never done a neck re-set. My problem is finding the insulation to protect the finish of the guitar while steaming off the bridge the first part of the fretboard. Anybody know where I can get it? Stew Mac don't know what I'm talking about.


Sent from my iPhone using Tapatalk

You can use paper for shims - well fitted and glued, paper shims hold extremely well and don't interfere with subsequent work.

Here's a shot of a thin fiber (it's phenolic resin impregnated paper) shim going into a Martin dovetail:



For what it may be worth, I've frequently seen shims in original Martin construction of all vintages, including wood, fiber and occasionally plain paper.

_________________
Cheers,

Frank Ford

FRETS.COM
HomeShopTech
FRETS.NET

Cool photo Frank I'll be doing my first neck re-set coming up shortly.


Sent from my iPhone using Tapatalk

If I can use plain paper for shims this opens up possibilities. I think Ill try a dry fit tonight to test the fit.

Perhaps I should have already done a test fit using paper to see how close or far I am to a good fit.
As long as I didn't use glue I can pop it back apart.

I've successfully used a sharp plane and then trimmed the shim piece to size. I worked on an old Regal that had a shim that appeared to be paper, I am not recommending this, but it stayed together for 90 years.

G