Woodworkers' Question (moving the bridge)

Mighty Melvin

Member
Messages
2,711
Hello.

I have a guitar with, the manufacturer says, an agathis body. They kind of messed up the placement of the import tune-o-matic bridge. Instead of a few millimeters farther than two-times-half the distance from the nut, it's a few millimeters closer. It will almost intone if I turn the saddles around but not really. Except for the low E which won't even get close.

So I have to either move the neck out or the bridge out, and I've decided to go after the bridge. It'll leave scars but I ain't so pretty myself.

When you do this, is it good practice to get a plug cutter and the correct wood and plug the original holes with a similar-behaving wood (agathis does not seem to be available retail), or do you just shove a dowel in there and call it done?

I wouldn't want the plug to have expansion/contraction breaks in the glue joint but maybe I'm overthinking this. But I don't want to do a hack job. I mean even more hack than not refinishing the guitar after I'm done, which I'm not planning on doing.
.
 

swiveltung

Member
Messages
14,484
Tough one. I'm no expert, but agathis is pretty soft stuff. A hardwood dowel is going to be difficult to stay on location if you are boring partially into the dowel and partially into the agathis. I would probably find the softest dowel I could, (pine?) glue it in with thick 5 second glue. Then find a special drill bit that has a good long lead point to keep it on track I have one but not sure what it is called.
It's pretty much like this with a longer point and less open area on the twist.
https://www.lowes.com/projects/images/buying-guides/Tools/drill-bits-buying-guide-inline-brad.jpg
 

202dy

Member
Messages
441
Plug is preferred. Preferred, as in, don't use a dowel.

Agathis is a conifer (soft wood). The problem is finding a small piece of agathis. The cheapest thing to do would be to scour some swap meets or flea markets to pick up a trashed agathis solid body. Failing that, domestic softwood will work.
 

Mighty Melvin

Member
Messages
2,711
A conifer, wow! I thought about putting out a call for abandoned agathis. You may consider this such, if you happen to have some. The only body I ever saw at a flea market, and I go a LOT, was a poplar Kapa.

There are sources for all kinds of information on wood behaviors. I only suppose I can find some for agathis and match it with something more available here.
 

9fingers

Silver Supporting Member
Messages
8,425
I would not worry much about using a dissimilar wood for the plugs. Different woods are glued together all the time. Do use a plug cutter so you get side and not end grain on the plug. A good fresh yellow carpenter's glue would work well with the plugs (or hot hide glue if you have the setup).
A brad point drill bit AND drill press will give you good true new holes. Clamp the body to the drill press table (band clamps or hand screw clamps would work) so it can't skate around as you drill and you should be good to go.
 

202dy

Member
Messages
441
A conifer, wow! I thought about putting out a call for abandoned agathis. You may consider this such, if you happen to have some. The only body I ever saw at a flea market, and I go a LOT, was a poplar Kapa.

There are sources for all kinds of information on wood behaviors. I only suppose I can find some for agathis and match it with something more available here.

You're likely to be purchasing the entire guitar. Actually, many of the solid body guitars from Asia are likely to have agathis bodies.

Assuming, of course, that this is a solid body guitar. If it is a semi-hollow, a maple plug in the block would be perfectly acceptable.
 

Rhomco

Making UPS, FEDEX and USPS richer every day!
Gold Supporting Member
Messages
2,174
Poplar is close in grain and density and you can get it at home depot. I glue mine in with titebond. After level sanding I harden the exposed plug with thin ca glue. Next I scrape it level and drop fill any low spots with more .ca. Repeat until you can't feel the plug or the glue line with you finger tip.
Good luck with your project,
Rob
 
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