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I am pretty excited about starting the Martin O 12 fret 24.9” scale guitar I’ve started laying out for my youngest Erin. (Being an unaccomplished archtop builder I thought I would endeavour to be mediocre at flattops as well).

I am using the Bluescreek outside mold which is bang on with Martin’s O specs. So here come a couple of newbie questions:

1).     How far below the centre of the soundhole (3-5/8” diameter) should the X braces cross?

2).     Should I shoot for a 90 degree angle for the X brace?

3).        The mock-up I’ve drawn is 87 degrees with the X brace crossing 3-3/4” below the centre of the soundhole (1-7/8” below the edge of the soundhole) or 2-5/16” above the front edge of the saddle. The X braces end in the upper bout above the centre of the soundhole and about 1-1/4” above the deepest part of the waist. On the lower bout the X braces cross over the bottom corners of the tail of the bridge (bridge is 6” in width). Should the centre of the X brace crossing be dropped closer to the saddle? If yes, how much?

4).        I’ve reviewed Sylvan Well’s excellent website tutorial on building a Double Tenon Neck Joint (Sylvan’s method is very similar to how John Mayes, Terrence Kennedy and Dana Bourgeois do it) and really want to give it a go. Does Sylvan’s method negate the need for the Upper Transverse Graft or Brace or should I beef up the width of the Upper Face Brace from the typical ?” width? (Sylvan’s instructions call for a block of wood 2 ?” wide and .425” deep and the distance from the end block to the Upper Face Brace in length that is centred and glued to the underside of the top plate).

5).       The bridge plate on some info provided to me suggests Martin used a bridge plate 1” wide, is this too narrow?

6).     Rather than using two Lower Face Braces splayed from the bass side of the X brace I am thinking of going with a Larivee/Laskin horizontal style of Lower Face Brace. (I’d like to brace the top as lightly as possible and am thinking this style of brace would be better protection against a potential hump below the bridge).   How far below the bridge plate (which is 1” wide) should the 1st and 2nd brace be located? Or is this over kill for an O style.

Your thoughts and advice would be most appreciated.

I will be over on Saturday after skiing, and we will draw up a plan buddy.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Geez I want to come too.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Thanks Tony and looking forward to it!

Bob -- my suggestion is to come to dinner and avoid skiing with Tony. My cooking won't kill you, skiing with Tony can He's a great builder and teacher --something just not right happens to him when he staps on the boards    

Seriously Bob we will plan an event at my place when the driving conditions are more predicable.   

Todd many thanks for the suggestion. I've got John's OM plans and will have another look. Brad Goodman sent me his drawings of a 1903 Martin O -- though the body size doesn't match my mold. As a result and in part the questions I asked above. I've pretty much got the stresses etc on archtop plates figured out...flattops are a complete mystery.

The beauty of the OLF is access to great builders such as yourself and avoiding wearing out the welcome rug with the expert down the street.