Bottom Radius and the Live Back

[DeanP]

Hello Trevor/Group:
I'm making my first attempt at a live back. Actually two, one on a dread style and the second on an OM. The dread back is braced and I'm nearly finished with the OM. As I was lounging around last enjoying a cold one, I picked up vol. 2 and was reviewing chapter 11. What I hadn't picked up the first time, was your description of back radius used for live vs non-live backs. Both the dread and OM I'm working on are being built with 15' radius backs. Obviously, not what you recommend.

My question then is can I expect to have a live back with your radial bracing layout using a 15' radius?

Thanks,
Dean

[Trevor Gore]

Hello Dean,

Welcome to the group.

15' should work fine. Just don't scallop the lower bout transverse brace as much as shown in the book or the back will be too "floppy". At a guess, I'd say scallop only about half as much, then trim in from there when you have completed.

[DeanP]

Thanks for the quick reply, Trevor. Headed out to the shop now and that's what I'll do.

I had all of the braces carved on the dread except for the lower bout transverse brace .

I guess it's my lucky day!

Thanks again,
Dean

[kiwigeo]

I've just finished a classical with a live back....15' radiuses and radial braced and it's very vibrant. Unfortunately I didn't follow Trevor's book to the T when thicknessing the back so its not coupling with the top as it should be.

[DeanP]

Hi Martin:
I followed the "program" and thicknessed my backs (black walnut) accordingly. Per Trevor's recommendation I left plenty of meat on the lower braces for future tuning.

It will be fun to see how this works out, especially with the two different body styles.

Dean