Official Luthiers Forum!

Hi all. Hope the christmas was a good one !. Personally I am happy its over ! still waiting for some wood from the postal service grrr.

while waiting, I am trying out some new shapes for a bridge and I was wondering what there is to think of as doing this ? minimum size on length and depth etc the one I am on now is looking a bit small ! 6.3"*1.4 and the wings are about 0.7" and it weights about 28g. As compared to a standard marting bridge its really small, so therefor I was wondering what impact a different shape and or size is doing for the guitar, I do understand that a large sized bridge would probably dampen the soundboard. But if this was the only thing, then why arn´t there more guitars with smaller bridges ?.

Lars.

I would be worried about a large enough glueing surface area to provide strength. I would also want enough area behind the bridge to resist the torsion effect of the string pull over the bridge. I have no idea what those areas should be but suspect a Martin sized bridge might provide a good starting point.

_________________
Steve Smith
"Music is what feelings sound like"

Lars, a standard martin bridge is 6.0 X 1.5, you're probably fine.
I don't use a martin bridge, so I could be wrong, but I just measured the MacRostie D-28 print for the bridge dimensions for you.

_________________
Jim Watts
http://jameswattsguitars.com

Lars I would design around these principles.

Main body 8-10.5mm thick x 38-44mm deep x 152.5-160.5mm long (cross the Xbrace)
Wings 4-5.5mm thick x about 19-25mm wide at min.deep

Stay with in these parameters and all will be fine.

Just for comparison, a lot of good guitars were made with pyramid bridges which measure 6 inches by 1 inches, I think. Typically these were OM or smaller instruments.

_________________
"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

There's a lot that could be said on this subject. I posted some of it just now under 'more on WRC for steel': the forum kept dumping me when I tried to add it to the original thread.

In terms of tone, keep in mind that the bridge is one of the largest braces on the top, and can weigh as much as all the rest of the bracing put together. The mass and stiffness of the bridge have a big effect on tone. Generally, all else equal, the heavier the bridge the less volume, more sustain, and more 'bass balanced' you'll get. Making the bridge longer or shorter can alter the stiffness of the 'wings' of the top between the bridge ends and the edge quite a lot. In this respect altering the bridge length is like thinning the top around the outer edges more or less.

It's easy to over-think this stuff when you haven't made many guitars, or even when you've made a lot! Just remember that the main job of the bridge is to tell the strings how long they are, and keep them in contact with the top. The standard designs do this pretty well, and if you stay more or less within those sorts of parameters, you'll be alright.

Thank you all for helping out !

Steve just wrote what I had in my mind though. the pyramide bridge that is 6"*1" !! ok its mostly on smaller sized guitars BUT it´s mostly smaller in the width not lenghts of the body, so the pulling stress from the strings should be about the same as for a larger sized guitar ?
Thanks for all the info , it really helps.
more is better .

Lars.