Acoustic Guitar Construction

Numero Quatro Chicory Bleu
11/12/24

When I started my third acoustic guitar I decided to build another with like components and same form but with a ladder-braced top instead of X-braced like #3. I made duplicate head and end blocks for use with #4.

A red oak skid from a pallet provided the sides for #3, but I was left with a less-attractive piece for #4. These sides had worm holes, and they split lengthwise when they came out of my Fox bender. As the splits were toward the back where they'd be reinforced by the reverse-kerfed linings, I used them anyway. When I epoxied the 1/4” x 1/2” neck reinforcement in #3 I used the remainder of the already-mixed epoxy to screed into the cracks from the exterior of #4. Some of this shows in the photo with the recently glued bindings, before cleanup. I may regret doing this if it shows thru the finish.

This guitar has parallel top and back made of 1/8” Russian birch plywood like #3. The silhouette is from a Santa Cruz OM. The body depth is 3-1/4”. The soundhole is 3-5/8” diameter. Bindings are cherry, .10” x .25”. Sides and bindings are plain-sawn. The end block is nominal half-inch Equadorian plywood, and the head block is laminations of 1” yellow poplar. Reverse-kerfed linings are basswood, 1/4” x 3/4”, kerfed with a chop-saw blade in my radial arm saw. Interior bracing is white pine from common lumber, selected for grain orientation to be quarter-sawn. Scale will be 25.4”.

I had part of a pint of light oak stain left from staining the stair rails 11 years ago. It was mostly just dried up sludge in the bottom of the can, but I reconstituted it somewhat with some mineral spirits and mopped it on the plywood top and back before brushing on the sanding sealer. Since these components are dark, I'm thinking of making a maple fingerboard and bridge for contrast.

I need to glue up neck stock next.

Looking good Will. Brace spacing looks about right, divides the top into two areas of different size.

Yep looks good, is going to be loud, I'm thinking.
I hoping that your headblock has a mortise that runs from top to bottom!! Or that the top is not glued on...

Dave, The slot for the tenon can easily be opened up, even if the top is glued on, no?

Well I was just pointing out that the block appeared to be upside down. Did not know if the mortise was that way by design, or not. Do you see what I mean or have I finally lost it?

edit: never mind. I see that the mortise does in fact go all the way. Tres cool

Constructed mating features today for the neck. The neck has a 3/4" wide tenon 1" long, is held in the head block with gimmicks from the local big box, variously called "barrel & bolt", "KD connectors", or other names. I put guitar #1, the square-neck resonator, together with hanger screws, as I used to do stair carpentry and they're the standard fasteners.

Guitars #2, #3, and this one use the barrel and bolt. These are strange animals - the barrels are maybe 10mm diameter, about 5/8" long, yet are tapped 1/4-20 UNC but not in the center of the length. The screw length is 2-3/8" mas o menos. One of my mechanical engineer friends puts his necks to bodys with socket head cap screws, Bellville washers, and thread inserts, but having installed Keenserts, Pem nuts, and other assorted stuff requiring special tools for proper insertion, these are quick and simple.

The tenon has a 1/4" dowel up 2-1/2" from the bottom toward the guitar body from the cross-drilled holes for the threaded barrels, though it doesn't show well, if at all, with my cheap camera. The neck will get a 1/4" x 1/2" x 12" piece of steel reinforcing epoxied in an as-yet-not-cut ploughed slot, like I used for guitar #3, and my Spanish V joint for the headstock. Wood is yellow poplar, plain-sawn, with a 1/4" red oak center stripe flanked by 1/8" teak strips.

I work in what started out to be a farm shop, though a tenant works the ground now. The humidity is what it is. The stove used to run on corn, but now uses wood pellets. Stuff glued and clamped gets set in front of the stove. The shop basically stays about 30 degrees above the outdoor temperature unless I crank up the stove. My router table is a sheet of particle board on sawhorses.

I bandsawed the neck in both plan and elevation views to taper the neck. Glued on the headstock and
glued some red oak veneer on that. Put a coat of sanding sealer on the headstock veneer. I had previously made a soft maple neck. Glued that on yesterday. Today it was raining so I had to rout the sides of the neck to the fingerboard in the shop. I usually try to rout outdoors because when I taught Wood Shop I had 30 students an hour to help clean up and I'm spoiled for cleanup help.

I've got one bit 3/4” long that has a pilot between the cutter and the shank that goes into the collet, from several sets of assorted Harbor Freight router bits, some old HSS bits from carpentry days, and one good solid carbide Freund down-cut 1/4” bit. The bit with the pilot cuts the sides flush with the fingerboard deep enough that the rest gets rasped away anyway.

I'm going to go see my new granddaughter next. Guitar #4 will have to wait until 2015 to get finished.
Y'all have a joyeous and blessed Christmas!