Buckling Top Problem

[Rich Middendorf]

I'm restoring a '40's Harmony made SS Stewart acoustic. It's a wonderful old guitar with an Adirondack top and one piece Honduran hog back, sides, neck. Braz fingerboard and bridge. It was unplayable when I got it and had been for a long time. The neck was loose in the dovetail. I did a neck re-set, remounted the bridge and when I strung it up the action was perfect and it sounded amazing. It has a small jumbo body, the old figure 8 Harmony style. 

A week later the action was getting bad again. I over set the neck to compensate for the ladder top belly and no truss rod neck. When I put a ruler on the top I could see the top was sinking under the fingerboard extension. I have included a picture of the UTB and I'm thinking of adding a second brace like the old Gibson bracing. 

I don't want to over-restore, or do anything that would kill the tone of this instrument, but it was a factory guitar in the day and while the materials are world class, the mechanical design was aimed at fast, inexpensive assembly, not longevity. 

Any other ideas how I could support this area?

[William F.Eden]

Well i think  you are on the right track as the brace you are showing is to  far back from the hole to give the top the suport you need .........................