Acoustic Guitar Construction

Making more progress finishing the top and assembling it with the neck and sides. I would be farther but ended up in a web hoster support nightmare when the hosting server was miss configured. I host the pictures for my posts on my harvestmoonguitars.com website. As different forums that I post on enabled SSL They could not find pictures on my site unless my site supported SSL. It did not go well. Now all is good.

There are a few ways to build in a "traditional Spanish style" , basically working top down on a solera or work board. One way the sides are joined to the neck and then the neck and side assembly is glued to the top, either on linings or placement of individual peones/tentalones. The other way that I am using is to join the top to the neck and with that assembly clamped on a solera the sides are added with peones/tentalones. I am doing the second method as I can assure that the neck is perfectly on the center line of top without having the sides getting in the way.

First task is to brace and voice the top. Previously I had thickness the top to my flamenco setting using tap method. Once braced I did the finial voicing just through feel and tap. I can not describe what I am feeling, I just want a bit of longitudinal flexibility and more horizontal flexibility. When I listen to the tap I looked for a strong start that died quickly. When the top is glued to the rims it will be stiffer which increases unwanted sustain for a flamenco.

I am using the bracing pattern I got from the Paco Chorobo Flamenco Guitar Building course. I made my first flamenco using this course and was lucky enough to have Paco use it for a small concert. I am not sure how the rosewood will change things but I wanted to start with what I know.



First off I glued on the two transverse braces. It would have been prudent to only glue on the top brace at this time to make carving the fans easier (live and not learn). Not too hard to work around.



To transfer the pattern I drew the same arc on both the plans and the top from the center of the top at the lower transverse brace. Measuring the distances between the braces at the lower transverse brace and where the arc crossed the braces, I was able to get two points for each brace and draw the brace lines.









I cut out and thicknessed a bunch of 5 mm wide fan brace stock and roughly cut it to length. I stack three or 4 together and cleaned up the gluing side as well (no radius, but I will push them into the concave dome in my solera.








I glued them in my gobar deck on my solera (forgot to take a picture)

I took them first to specified height of 6mm. Then I felt and tapped the top. I left the center for structure but took the outside braces to 4.5 mm and the two close to the center to 5 mm. When happy carved the ends of the braces to about 1 mm and I gave them a triangle (more gabled house) shape with a plane.





I tapered the end 20/30 mm of the brace to about 1 mm.



A ledge needs to be routed into the neck heel to accommodate the top so that the top is level with the fret board plane. I uses a router in my Bishop Cochran base. Notice that I really push the guide out from the base to make it easier to cantilever into the ledge I am routing, staying on plane with the neck.

First I used a bit of the top cutoff to set the depth stop.





I glued the top to the neck using a new method. In the past I would clamp the neck on a straight work board with a center line penciled in, then I would clamp the neck on the work board and centered the heel block center line that hopefully I transferred from the top correctly and I would get on my knees and look under the work board to make sure my neck was on center. On this guitar wanted to make sure the heel block center was marked correctly I lined everything up from the top using a straight edge to assure I was centered. Seeing this, it occurred to me I could just glue this up with the same clamping arrangement. I am sure my neck is centered and straight.



Now was the time to make sure the sides and the top neck assemblies could fit on the solera all centered up.









With every clamped into place I rough profiled the back to a 25' radius, I also set the depth of the guitar at the tail and heel. When finished I will be 95 mm and 90 mm. Five millimeters deeper than my Blancas. When profiling that back the neck and clamped on my solera giving me a classical guitar neck angle; I also have a 1 mm shim at the neck join location to give me a touch more forward angle for flamenco setups. As the Spanish heel slipper and heel is also being profiled at this time it is important the guitar is clamped in the correct geometry.





Even though there was a sheet of paper on my bench that said taper neck to final thickness before gluing on top; here I am doing it now with a safeT plane dragging along the top.



I get my desired taper using a shim on a small board that you can see in the above and below picture.



With the neck tapered I could attach the top to the rims with peones. I had to make a batch of peones. Also not shown is before clamping the side to the top, I put glue on the tail block and the sides. I probably do not need glue on the top of the rims as all of that get routed off for binding. I just find I have less of a risk of chip out when routing the bindings if the sides are glued to the top.

I am a little behind posting the guitar at the time of writing is in sanding prep stage. I will break this up into a few posts.
One by one I finished installing the peones or tantalones. I install them a little looser in the lower bout to lower the impedance to the sides (allow the sides to vibrate, stealing energy from the top)



With the top, sides and neck together I moved on to the back.

Center strip



Ripped a set of braces



Located and cleared the center strip for the braces. I use a scalpel to cut the center strip and a chisel to clear







I use a handy radius jig to set the 25' radius on the back braces. I first get close with a chisel, pencil mark the bottom of the brace and sand in the jig until radiused. I used to use a radius dish, but I tended to roll the edges a bit making a sloppy looking joint.







I use a plane to to set the brace height and round the top and a chisel to taper the ends down to 2 mm.









I installed reverse kerfed linings. I had to bend them a bit on a hot pipe to keep them from breaking. I bent them and let them sit on the outside of the guitar over night. I installed them the next morning.



I had profiled the rims with a radius dish earlier so I mostly planed the linings and then touched up and tested the radius with a 25' dish.





I made sure that I had good center lines everywhere so that I did not loose center after closing the guitar.



With the back clamped in place I marked the brace locations



I used a pencil grinder to cut into the linings





Gluing on the back in a spanish heel construction sets the neck angle. It is important to get this right as it is hard to reset. My solera has a built in neck angle for a classical guitar, A flamenco as a bigger forward angle as the string height from the top at the saddle is lower than a classical

With this in mind I added 1.5 mm of shim at the body join to force the angle when I close the back.



With the shim in placed and the neck clamped to the solera I glued the back to the guitar.

With the back on I used my Fleishmann binding jig to cut the rabbets for the binding. I first cut the channel for the bindings and changed to a smaller bearing to cut a rebate for a black red black set of strips.







The traditional Spanish style build is great up to the point one needs to hand work near the neck for the binding and perflings. It is mostly free hand work that can go wrong in a hurry.

I use my clear template as the template for the cut. I align on the already cut purfling rebates and use a scalpel to cut through the top.



I use a chisel to clear the top for the purfling and the binding.



Then I use a large chisel as both a straight edge and a cutting instrument to mark out the binding depth to the neck.



Not shown but I use the same chisel to remove extend the binding channel to the neck. I alternate clearing wood and maintaining the cut line.

I use a combination of a razor saw and a 2 mm chisel to clear out the wood under the fretboard. Car must be taken to avoid hitting the neck cheeks to have a clean joint with the binding. Because of the fret board their in no need to clear it to all the way through.



I test the fit with a bit of binding.





I cut the binding to length and install with the purflings.



The back is the same, easier because I am not using purflings, but a bit more finicky as there is not a fret board to hide the work near the end of the bindings. I extended the back to include the heal cap so I terminated the bindings just inside the heel cap. Care must be taken to insert from the center the same amount. The eye is really good at picking up broken symmetry. I used a scalpel to mark and cut the binding inserts and then a 2 mm chisel to mark and cut the end and to clear channel. It was a back and forth operation.







Not shown I installed the back binding. Did a touch of leveling the channels were very close.

I have a removed fretboard that I use as a template for my flamencos. I use it as a rough guide, before fine tuning the nut and 12 fret widths.



For the first time it dawned on me to use my shooting board to plane the fretboard to size. Previously I put it in a vice a planed away. (noone told me?) spending energy keeping the edge square to the top.




I ultimately want a projected gap at the saddle to be 2 on the bass side and 3 on the treble side. This will give me around 8 mm string height at the saddle location for a 3 mm bass action and a 2.5 mm treble action. Without thickening the fretboard right now I have 5 mm. So I need to thin the fret board 2 on the treble side and three on the bass side. Currently the fretboard is 8 mm so I will be perfect with the treble 6 mm and the bass side 5 mm.



I taped a one 1 mm shim to the base side. and ran it through my drum sander until the treble was 6 mm thick.





Right on target

Neck carving.

I positioned the fretboard and pined it with some drill bits. With the fret board in place I rough profiled the neck with a spokeshave and a rasp.



Grabbed the heel profile from one of my other flamencos and used a chisel create the inward curve on the heel.



Then only because I really wanted to use my new Sloyd carving knife I played a bit on the heel. It is a revelation after struggling with a rasp when the neck is attached to the guitar.



I marked some layout lines.



I must have been in the zones as I did not take any pictures but using almost a;; edge tools, spokeshave, chisels, gouges and my handy sloyd knife I profiled the neck to a template I had. I am making a rounder neck than I usually us for my classicals. I had a template that looked good.





Here is where I end up.

Looking good, John.

Hey John,
Is carving the neck before attaching an option?
Herman

btw beautiful binding.