Acoustic Guitar Construction

Even if you use 28' radius braces on the top -- Martin uses 52' Taylor 0' and 65' KMG 40' The top of the rim is not beveled -- its sanded flat. Larrivee, Hoffman, and most other do the same Huss and Dalton does it both ways. Please read:

http://www.kennethmichaelguitars.com/neckfitpart1.html

There is really nothing in the brace pattern to hold the perimeter (think about it) of the sound-board to any given contour -- plus the sound board surface is rather complex -- the structure benefits from a flat smooth glue surface around the perimeter. Yes there are those that sand a bevel -- internet convensional wisdom.

Plus the real world math is -- a 28' bevel is .008" higher on the inside edge of the rim, (side plus kerfing). In other words considered flat in wood working tolerances.

I am only posting how I do it, not to compete with Ken's methods. I think he knows this. His instructions are tried and true and what you should follow building his kit.

I just wanted to share that in lieu of having a radius dish, I have used a 15' radius sanding stick, or bar if you will, to contour my back and a 30' for the top, positioned on a post similar to what Ken has in his kit. This has worked successfully for me thus far, albeit I'm sure not with the precision that Ken's setup will produce. I pre-cut my sides to about 1/16" of final height, shaped as necessary so at the area of the waist, there is a slight rise to match up with the arched shape of the back. Then working the sanding bar around the rims, I bring them down to the correct height and maintain this necessary geometry at the waist so the back fits correctly. It probably is not perfect, but after 7 guitars....not very many really, I think I can continue this way and be successful. I may put out the $$ some day for the dish, but I'd rather buy wood!

Kevin

Kevin I agree with your method, actually the "Success Kit" package comes with a simple sanding bar. The key however is that the kit and your sides are at least roughly profiled to begin (rise at the waist). I have to admit I've never completely profiled the sides after the rim was assembled -- so I am learning here as well.

kencierp wrote:Kevin I agree with your method, actually the "Success Kit" package comes with a simple sanding bar. The key however is that the kit and your sides are at least roughly profiled to begin (rise at the waist). I have to admit I've never completely profiled the sides after the rim was assembled -- so I am learning here as well.

Early on before I had a band saw I dealt with unprofiled sides. I used two methods that worked. The first is as described above, sanding the sides in a radius dish. To be somewhat accurate I marked the height I wanted on the heel and tail block and while sanding also maintained a watch on the height of the sides to make sure I was not creating a wedge. With a lot of sanding it did work well. The second method I used was to roughly plane the rims down to within a slightly more than a 1/2" margin of my desired dimension on the tail and heel block. I laid the rims in the radius dish and using a pencil lead inside of a small square of wood I traced the desired profile onto the rims. I then used a plane to get the rims close to the pencil line and used the radius dish with sand paper to finish the job.