Acoustic Guitar Construction

I finally got back in the shop and started a ukulele for a repeat client. She let me chose the wood so I dug through my stacks and paired a cool curly redwood top with a Hawaiian Koa back set and a seperate set of orphaned sides. I ended up swapping out the neck blank for one with an ebony strip in it.



I started on the neck blank. I am sorry I did not take a lot of pictures. I started with scarfed jointed blank I had in my stash and using a plane thicknessed the head stock from the top and then tapered and thicknesses the fretboard face of the blank. These two complementary actions kept the scarf joint end right under the nut location. I had a small block of mahogany that I am using for a built up heel.



The ukulele plates are a bit small to work well in my LMI jointer jig, so I used a tensioned tape jointing method.

I used a plane and a shooting board to clean up the edges for gluing and then with the plates tilted relative to each other taped, glued and flattened them. Then tension from stretching the tape holds the plates together until the glue cures.













I started to lay out the neck but had to stop there.

I am making a lot of progress on the ukulele, less progress on the blog so I thought I would take a bit of time to bring the blog up to date.

First off I want to complete the assembly of the neck and the sides. I am building this uke on a work board that includes a mold much like my traditional flamenco or classical guitars. Unlike the way I build flamenco, I will first attach the sides to the neck instead of attaching the neck to the top first. When making flamenco guitars I use tentallones to attach the sides to the top and neck combination. With this build I will use kerfed linings which I typically install with the sides attached to the neck. (although ultimately I could have attached the top to the neck as I ended up attaching the top using kerfed linings but with the top on the work board with the sides and neck in the mold)

After determining the 12th fret location I used my table saw sled to cut the slots in the neck for the sides.







As mentioned above I am using a work board and mold for a traditional Spanish style of build



I have a good side template for the martin tenor ukulele with a tapered and radiused (25') back, so I cut the sides very close to the profile, thicknessed them to .075" and bent them in my small Fox side bender I bought from Blues Creek Guitars. I just fritz with water and wrap the sides in a paper towel. I use stainless spring steel for the slats. I have found that soft steel and aluminium foil will turn koa green. (a sandable green, but who needs the stress.)



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While one of the sides was cooling in the side bender, I fretted and radiused the fret board. The fret board was radiused to 20".



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I went ahead and tapered both the fret board.




I also pre-install the end graph on the tail block. I hate cutting out the recess for the tail graph, this method allows me get a great joint on both sides of the graph.







I first use a combination of my band saw and a disk sander to fit the sides perfectly into the mold.







I adjust the sides for the end graph and the neck slot. I just use the disk sander. As long as I remember to have the straight top side down I get a square edge.





I fuss with the joint until it is centered and clean.

I do the same to fit the sides to the neck and when happy I glue the sides one at a time to the end block. To get the side square I only need to make sure that the side is tight against the end graph.



I need to wait on the top before gluing the sides into the neck slots. The sides sit on the top and the top needs to be set on a shelf routed on internal neck block. I will pick this up in the next post.

As mentioned in the previous post I need a properly thicknessed top to correctly align the sides into the neck slots. Before final thicknessing of the top I like to first install the rosette to give some margin to sand the top after the installation of the rosette. The rosette is a very simple one ring using ZipFlex Abalone Purfling and 2 black fiber perflings. There is a bit of pearl to sand, but to be safe I routed the channel a touch deep so that I could sand the top to the zipflex. Also I took care that the zipflex was well seated as it needed to be even on the top. The rubber backing is not very pretty if you sand through the abalone.





Sanded and scraped with a wash of naptha to show the abalone.



I used my drum sander to thickness the top to 2.2 mm. My ukes are closer to 2 mm but redwood is not quite as stiff as spruce. The top felt about right at 2.2 mm. No magic scientific thicknessing, just experience and feel. With the top thicknessed I used the top to set the depth on a router and routed a shelf on the neck for the top.





I used a chisel for the work close to the visible neck to avoid damage.



After a check of the fit with the neck I used some super glue to attach the sides to the neck. Note the wax paper on the top to keep from gluing on the top as well.





I used a small block plane to profile the sides to close to the correct height. I did not have much to trim as I profiled very close to the true profile. I still gave myself a bit to clean up in case I bent slightly off the center of the waist.



I used a 25' radius dish to clean up the rims. I removed the top but I still have a piece of the tops offcut and I have the neck clamped to the work board to assure the neck is in the correct position. When sanding I am shaping the neck block as well so the neck block needs to be properly positioned





Next up will be bracing and attaching the sides to the top.

I bought a tripod adaptor for my phone I took some of the pictures using it. My phone has a pen that acts like a remote with the camera app open. Yes I do work in my pjs



I made some brace stock using my band saw and my thickness sander. I got a set of thickness blocks that I use to set my band saw fence. I cut slightly big and finish up in my drum sander.
I use a block plane to set the height of the brace









The outside fan braces need to cross over the bridge location. My template is for a 14 fret ukulele, so I laid out the braces for a 12 fret ukulele placing the bridge and assuring the fans crossed on the ends of the bridge.




I also decided I would tie the upper transverse brace to the heel block. So I marked off its location.



Used a go bar deck to glue the braces on.



I used a chisel to carve the fan braces. I locate the peak under the bridge.



Carve the ends of the transverse brace.



All cleaned up.



Before gluing down the sides. I double checked that I could get everything lined up and that the top would fit properly on the heel shelf. This took a touch of cleanup. I used a sanding beam to make sure that the top of the sides were flat. (the sides are in the mold top side up for sanding.)



Properly positioning everything before the glue up.







I even got approval from Sua



When all was ready I applied glue to the blocks and the top of the sides and replaced the rims in the mold of the top. With every thing properly in alignment I glued down the kerfed linings much like I glue down tentalones in my flamenco guitars. The tight bond grips very quickly.





Now I am caught up in the blog. Ready to start the back.

I managed to close the box today. Most of the work was on the back and the back side of the sides. The first task was just to flush cut the top to make it easy to get the ukulele in and out of the mold. I hate changing router bits, so I have a porter cable cable router with a spiral flush trim bit all set up in the router.



I thicknessed the back to 2.2 mm and profiled it on my bandsaw. I save a bit from the top of the back that I might use for the end cap.





I grabbed one of my narrow back strips (cut offs from previous guitars), cut it to length and glued down in my gobar deck. Not really necessary but I glued it in the 25' radius dish.







I had some 3/8 brace stock that I cut to length and use my LMI brace tool to radius. I like this tool as it gives me a flat bottom. I used to use the radius dish thinking that it is being glued in a radius dish. I found it was really easy to roll over the edges of the brace or tilt the braces sanding in the radius dish leaving an ugly glue line.



I marked out where I wanted the braces and using a scalpel, small machinist square and a chisel cleared a channel for the braces. I even got some help from Sua, but she got bored.







I got them all cut and I glued up the braces in the go bar deck at the end of the day. My spouse sent me out to pick some apples.





This morning I trimmed the height of the braces to 3/8" Did a bit of shaping and scalloped the ends to 1/8" My guard is set just to the height I want the braces so unless I muck up I get consistent ends.







Moving back to the body I installed some kerfed linings, used a plane to get them close and then cleaned them up with a 25' radius dish.







Moving on I marked out the brace locations and used a pencil mill route out the channels









No pictures, but I cleaned the insides of the top and the back up with 240 sandpaper, installed the label on the back and glued it on.



After the glue cured for a bit more than an hour I pulled out if the mold flush trimmed the back and called it a day.

A spanish heel makes it really easy to get a perfect neck angle and a flawless side to neck joint on my ukuleles with their flat neck angle. I am really happy with it until I am doing all of the hand work near the neck to bind the body. Also it makes it a little harder to prep and finish.

At the time I bent the sides I had not picked out the binding so I had to bend them before starting the binding. I picked up a whole batch of very dark Indian Rosewood at a Seattle Luthier auction at Gurian Instruments. I choice 4 that matched nicely. I just spritz with water and wrap with a paper towel. I am keep the scheme simple basically framing the figured wood.







While waiting for the binding to binding to cool after bending I completely leveled the sides. To avoid sanding the bindings after installation the sides really needs to be taken to finish level before binding. Nothing worse than chasing level with the binding on.







Happily no chip out routing the redwood for the binding with my John Hall Fleishman binding machine. I just use a LMI rabbet bit with a bearing.

I start thinking about my choice of a spanish heel when I start binding the near the neck. I use a scalpel with a fresh blade against the top template to cut the inside line of the channel. This is the most important cut as it is hard to hide.



I also use the scalpel to continue you the binding channel on the side. This is cut is important as well but slight error s can be hidden. In this case I cut close to the line, clear with a chisel and then use a chisel indexed to the router cut to extend the channel.



Clear the channel



Fine cut the inside edge of the channel



The binding on the top needs to endup under the fretboard. I carefully use a razor saw and a 1 mm chisel to clear enough of the channel to inlet the binding.





I glued and taped up the bindings.





The back is done the same way. I am having the binding wrap the and join at the top. If I had a classical heel I probably would extended the back on to the heel and just inlet the binding.











I played around with a thin chisel until I would clear the channel between the back and the heel until the binding fit properly. (watch the sides of the heel as a nick there is visible.





While the glue for the binding was curing I prepped the top for the fretboard and glued the fretboard on. The blue tape is a fancy sanding shield. I used it to make it easier to remove the shellac sealer on the top under the fretboard.







This post is long enough.

I rough profiled an East Indian Rosewood headstock veneer and glued it to the headstock. I used a bench sander to put a 15° angle on the nut edge. I used a 4 mm setup block to locate the veneer and glued it to the headstock.





I used a block plane and chisels to shape the headstock to the close to the final profile. With a template one would think I could use a flush cut router bit to shape the headstock. But in the past I had chipout with the router and move to the plane and chisel.





It is starting to look like a ukulele


I started to rough profile the neck and decided a should work out the heel cap before moving on. I saved a the back cutoff and used it for the heel. Cap. I decided on a low profile arc for the heel cap.

I used a rabbet plane to take down the heel down a bit and profiled the heel cap.









With the heel in place using chisels, spokeshave and sandpaper I profiled the the neck



It seems I always wait for a Sunday morning to cut out a logo.













Here is where magic happens. I was not happy with the way the previous headstock balanced with the top. I though having EIR would work but I was underwhelmed. So before installing the headstock, I found a really nice Brazilian Rosewood blank with really nice colors and over all shade that complimented the redwood and provided balance between the EIR fretboard and the top. So I swapped out the veneers.



New



For comparison Old headstock