Official Luthiers Forum!

Hello everyone. I’ve been tinkering with building acoustic guitars for a few years and have learned a ton from my own mistakes. I screwed up the neck angle so badly on my first “from scratch” guitar that I compensated by shimming the bridge about 1/2” off the soundboard and installing an extra tall saddle. Apparently the saddle was too tall because the guitar has been in my closet ever since the saddle shattered under string tension and sent bone shrapnel flying all over the living room!

After years of reflection and self-medicating I’m now emotionally ready to fix it. Hence, my question to all of you fine experts.

The fix will consist of an entirely new neck and bridge. Although the scale length will be the same, the actual chances of me getting the nut in the exact same position are slim. So, I’m expecting to have to relocate the bridge a little. The pin holes in the soundboard will probably turn into over-sized ovals as a result. My plan is to leave the existing holes as is and install a platemate under the bridge plate. The idea is to trick the strings into thinking there are still just 6 little holes in the soundboard instead of 6 larger ovals.

I don’t want to have to somehow fill in the existing holes. What do y’all think?.................about the fix planning not the shrapnel incident

I think getting the nut in the right place should be pretty easy. Make your neck to the proper dimensions (tolerance will allow some variation). Now when it is time to pin your fretboard to the neck prior to gluing, locate the nut end the correct difference from the bridge. You can let the nut slot width float as it is easy to make a nut of any width. So scale length bridge to nut, you are now nuts on.

as to side to side location, flossing the neck should allow you to register exactly on the cl of the bridge.
Mike

Some of the repair guys and gals can correct me if I'm wrong, but I don't believe you'll need to install anything under the bridgeplate. Those nice, burly 3/16" pin holes in the bridge itself will keep them in place just fine. Adding mass to the bridge plate may considerably change the character of the guitar.

I would do the same thing that Imbler suggests. Just slide the fretboard to the right spot to get the compensation correct and mark it off. Then finish off the neck around that. You can leave a bit of fudge room at the neck end and when you finally glue the FB down you can place the headplate right up to the width of the nut.

Perhaps I should have given a little more info. The neck I planned to use is pre-carved with bolts and everything. There's not much fudge room with the fret board or nut placement.

That being said, your suggestions have me rethinking my plan. I could save the pre-carved neck for my next guitar since I'll more freedom with bridge placement. Then I can take your suggestions of using the original bridge location on my project guitar and set the scale length using the fretboard glue up.

That being said, I'd still be interested to hear people's opinions regarding moving a bridge without filling in the existing holes. Then using a platemate.....or not even bothering with that as James suggested.

If the new pin holes are now closer to the nut then this is a non issue. If closer to the tail block they should be filled and bridge plate reinforced with a small piece of 1/16" plywood to assure that the ball ends rest against some structure so they can get a good grip.

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

If the neck was designed for that scale length then you might just get lucky and not have to fudge it much. You could for example use a 1/8th in nut for extra wiggle room or conversely you could add a back stop to the nut like you see on Selmer guitars. In addition to that you could use a 1/4in saddle.

I would leave the bridge position alone, locate the fret board using the twelfth fret + compensation distance from the bridge and let the nut float. Your 14th fret to body joint maybe off a hair, but probably not much, that is, assuming it's good now.

_________________
Jim Watts
http://jameswattsguitars.com

You may have already done this, but if it was me I would go back and start near the beginning. I would remove the old neck and bridge then Lay a straight edge along the fingerboard extension part of the upper body and then check how much space you have at the center of the saddle location. That will help you know what neck angle you need and thickness of a bridge you will need.

If the angle is not right you will need to compensate somewhere before you continue.

Once you get that looking good then I would put the neck on and check the clearance again at the saddle. You can use the stewmac calculator to see how far from the nut the first and sixth string saddle Position should be.

Don't forget that as you shave and floss the shoulders of the heel the saddle location may change. I would get that right before moving to bridge location. Since you are making a new bridge you will have some latitude as to where you drill the pin holes in thee bridge. You may be able to match the holes you have. If not just drill them to a uniform size, maybe 1/4". The cut some pieces off a maple dow and plug them.

_________________
Joe Beaver
Maker of Sawdust

So much great knowledge guys. Thanks for sharing.

If you have to re-do the pin holes this thing works great. $$$$$, but the concept and some ingenuity lends itself to pulling it off with creative tooling.

http://www.stewmac.com/Luthier_Tools/To ... Saver.html

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

If you make your own bridge - you can make up a bridge with a thick saddle somewhere between 1/8" and 3/16" thick. That will give you room for compensation.

Then - make your bridge so you can use the existing holes.. And rout the saddle slot so the calculated compensation is on the center line of your saddle slot....

If you are using a pre-cut fretboard and neck - the nut position will be very close to right... Usually within 0.020"... That's probably better than your bridge gluing accuracy.

So unless your original guitar had the body joining fret way off - it will probably work out fine.