Official Luthiers Forum!

I'm making a flamenco bridge and got over enthusiastic shaping it to fit my intended top arching. As a result, one of the wings is a bit thinner than the dimensions in the plans I'm following. The wings were supposed to come out at 0.1574" (4 mm) but the bass side has a low spot at 0.148" and the curve is still uneven on the glue surface. This is my first build so I have no frame of reference as to what is too thin in this area.

So...Still usable? I figure I'm still ok, but would feel a lot better if I knew how thin I can go. I would deeply appreciate it if some of the more experienced builders could post their bridge dimensions.

Thanks in advance
Jake.

Jake,

You are still fine. I've done bridges as thin as 5mm at the fattest spot of the tie block, so the wings were more like 2.8--3mm. By the way, unless you've got super-pronounced doming on your soundboard, there is no need to arch bridges. Just a little bit of scraping to make the gluing area very slightly concave (we are talking a few passes with a rounded scraper) and you are good to go. Once the bridge is glued-on, and with a bit of string pull, the bridge will naturally take on the arching. If your soundboard is so stiff that you cannot glue a straighter bridge on (soundboard fights back, and does not conform to the straighter bridge, and vice versa), then you got bigger future problems to come with regards to guitars sound (way over-built, way too stiff).

_________________
Flamenco and Classical Guitars
Maker and Restorer

4mm could be kind of too thick for a flamenco, 3-3.5 is OK with average density rosewood, especially if you have some internal patch.

_________________
Build log

Thanks for the input guys!

Peter: Any idea what your bridges weigh on average? Thanks for the tips about shaping the underside as well. Seems there are two camps on things like this. Building a guitar with parts in tension vs. no tension at all. My soundboard is cedar and roughly thickness sanded to 2.5 mm. Doming is moderate so I didn't have to shape the gluing surface too much.

Alexandru: I'm following the Reyes plans drawn up by Tom Blackshear and I agree about the bridge seeming thick. The tie block and saddle section are much beefier than on the two Spanish made guitars I own. However, I think Blackshear states on his website that the Reyes he examined had a higher than average bridge for a flamenco.

Oh, I guess I should mention what wood I'm using. The bridge is padauk. I remember hearing that Brune thought it had a nice balance of properties that would be advantageous to flamenco guitars. I think it's the same wood that builders in Spain call "Coral"?

Jake.

Well here is the problem drawing a plan, and using one. Wood varies. I have made bridges with rosewood as light as 670Kg/m3 and as heavy as 1100Kg. That thick Reyes bridge could be made from extra light rosewood. Or maybe not. But to sum it up, it is in general considered that flamencos need lighter bridges than a classical, definitely under 20 grams.

_________________
Build log

I thickness to 3mm+ or-.
I do arch the glue joint on the bridge so as not to add any stress to the top that will change the tuning I have done to it!
I use a 25' or 28' arch;depending on what the clients needs.
Forcing a joint only adds stress.
Plus the bridge is only 17cm long X 25-6 mm wide.
tie block is 74mm x 6-8mm
Lite weight rosewood or even Walnut.
This is the size & stiffness &weight that works for my "Flammers"

Mike

_________________
Mike Collins

Jake,

The Blackshear/Reyes plan does indeed give you a much more classical style bridge, and I have heard it said that the guitar overall actually has a more classical feel than flamenco. Nevertheless, they are nice guitars. I've built two of them, and had a chance to have several flamenco players as well as a few builders play one of them while I was in Granada for the first half of this year. It was generally very well received.

The bridge could stand to be quite a bit lower/thinner than the plan indicates, though. So I think you are OK - even on the right track.

_________________
Jim Kirby
kirby@udel.edu