sound board top bracing

Paul C · Post by **Paul C** » Sat Mar 31, 2012 10:26 am

what do most of you guys use for radiuses on the top braces

John Parchem · Post by **John Parchem** » Sat Mar 31, 2012 10:30 am

I mostly use 28' for steal string guitars tops.

ken cierp · Post by **ken cierp** » Sat Mar 31, 2012 10:53 am

All our KMG kits are supplied with 40' pre-contoured soundboard bracing -- the internet standard has become 28' which has been inaccurately repeated as the Martin standard. Martin braces are pre-contoured at 52' merely to prevent a concave appearance. As one might expect the majority of the sound-board dome comes from the pull/tension of the strings. The main purpose of a dome sound-board is to increase the area of the plate --so if the humidity drops and the sound-board shrinks it will tend to flatten out before it cracks.

Paul C · Post by **Paul C** » Sat Mar 31, 2012 12:25 pm

Do all braces get radiused on the top

ken cierp · Post by **ken cierp** » Sat Mar 31, 2012 12:36 pm

X braces and tone bars (bass bars) The shoulder brace generally is flat with a tiny slope at the out edges to blend with the upper bout end of the rim, which should be fairly flat to accommodate the "flat" slope of the fingerboard extension.

John Parchem · Post by **John Parchem** » Sat Mar 31, 2012 3:43 pm

I used 40' for my bass guitar, top and back. I use 28' mainly because I am building guitars the way I was taught by Rick Davis. I have no problem with 40'. I am planning on making a 00 12 fret to the body. On that guitar I plan to follow Ken's method to obtain the correct geometry.

Acoustic Guitar Construction