Acoustic Guitar Construction

I am starting a spruce and tulipwood concert ukulele for a friend. It may be a little bit fancy for me as she is really in to having a shell rosette and purflings. I always thought tulipwood was poplar and rather plain. This wood is figured with good tonal properties. After helping someone on line with some plans, I was sent the set. Maybe some one recognizes this wood. (I have since learned that this is, DALBERGIA DECIPULARIS ORIGIN: SOUTH AMERICA. A true rosewood.

Tulipwood is an exotic wood native to the tropical region of South America, mainly Brazil. It is a hard and heavy wood, with a rather fine texture. The sapwood is a solid yellow color, while the heartwood color ranges from a pink to a darker red, with a straw colored background. Tulipwood is excellent for wood turning, as well as knife handles, furniture, and cabinets. It is a lustrous wood, has excellent polishing qualities, and glues well.


I have never made a concert before, I once bought a complete set of Martin Ukulele forms at an auction so I was some what ready. I got a mold from John Hall modified it and combined it with a work board for a Spanish neck joint. In the background you will see I have a second mold that I will use if I ever do a bolt on.



I used an old record plane to joint the plates. I used my guitar plate jointing jig to clamp the plates together but it really was too big.







Here is most of the tonewood I will use. A couple of years ago I accidently rift sawed large mahogany neck blank. I also had a nice plate of ebony, so I used two rift saw mahogany pieces and the ebony to mack a neck blank. I will need some thin wings for the head stock to get enough width.



I used my bandsaw to profile the top and the back.



I installed a Paua Abalone rosette with black fiber purflings. I used my bishop cochren router base to to cut a 1/16" + 1 mm channel. I carefully set the diameter of the rosette using a set of calipers. I am using a 1/16" bit. I cut to the inside line, make the diameter 1 mm larger and cut for the purfling. I use a bit of the shell to set the depth.





Once routed I tested it and ultimately made it a smidge wider to deal with swelling from the glue.





Once the glue set I leveled the fiber strips and cleaned out (well sort of cleaned out) the channel





Then I just worked my way around breaking the abolone into the channel. I would start at one end jam as much as I could along the channel until the strip broke. I would use that pointy tool to push in the piece and once in, push back tight against the previous piece and repeat. I used thin CA to set the shell as I went. The spruce was sealed with the purfling and the glue I used to install the purfling.





Level sanded.


I used the same bit to cut out the sound hole. I set the bit depth a little more than my final top thickness. I sanded the back of the top until the sound hole dropped out.

Good work John,
The back looks, for all the woods I used, mostly like Ovankol.
Zebrano has also such a color, but I never saw it flamed/curly.
As long it has a good tone, you will be fine imo.
Herman

Thanks Herman,

I got a little done yesterday and I may have a bit more time this afternoon.

I profiled, thicknessed and bent the sides for the rims.

My eyes are not what they once were, so instead of penciling in the profile lines I just taped on the template. Really easy to follow, with careful placement of the waist, I ended up with perfectly book matched and profiled sides.



To keep the book match through sanding I marked it on the side of the sides. I sanded to .080" as that is the thickness of the blade I use to cut the heel slots. Also a good thickness to bend. On a bolt on I might go as low as .070" for a ukulele.





I use a John Hall ukulele side bender from Blues Creek Guitars. At an ASIA auction I bought at a very good price a complete set of ukulele bending forms and molds that John Hall donated.





I used just a sprits of water and paper towel, I starting with the waist at 225°F I bent the waist most of the way, lower bout then upper bout and a tightening of the waist. I set the temp at 280°F and let it set for 12 minutes.

After cooling I removed it from the side bender with very little spring back. What ever this wood is it is really easy to work with.



With both sides bent, I used the molds center lines to mark one of the sides. I cut close on the bandsaw and finished on my belt sander. With the one side trimmed I used it to mark the other side. I cut the second side a little long and touch fit on the belt sander until it fits in the mold.







With the sides trimmed I rough profiled the neck and used my special purpose sled to cut the slots.









I trimmed the heel side of the sides back 5 mm and fit it all into my new work board and mold.

I have mostly been doing website maintenance the last few days, but I did get a bit of time on the rims and clean up the neck a bit.

Before I get ahead of myself and glue the rims to the neck I decided to do a bit more work on it. I use a safe T planer for both the head stock and the taper of the neck. I shim up the nut side of the neck to give me the thickness. I have measurements for the 1st and 7th fret of 11 mm and 12.5 mm respectively. As shown in the first picture the distance between the 2 frets is 105 mm, the distance from the 1st fret to the end of the neck 200 mm. So I calculated the slope of the taper rise/run and determined a shim height needed when pivoting on the end of the neck by taking the 200 mm multiplied by the slope. So 2.88 mm. I glued the shim right on the 1st fret location.



Then I planed away with the safe-T planer where I could until I had my desired thickness.



I also made a few passes on the head stock to get close. I need the veneer to do the final thickness. I left a thick area around the nut to give me options for the transitions between the neck and the head stock.



I made some wings for the headstock with some cutoff from the original neck blank.





I really hate routing out the end graft late in the building process, so I generally glue it to the tail block and then glue the sides to the tail block. If I am careful and get the end graph on square it is really easy to glue the sides to block one at a time and still have the rims square. Pictures show it better.

First I use a machinist square to glue on the end graft square.







I use my belt sander to cleanly take off half of the end graft from each side. I scratch a line. Make sure the top is down as it is square to the center line





One side then the other and done!

I continued to work on the neck getting it ready to glue on to the top.

I glued on the headstock veneer. No big deal. I used my drum sander to thickness it to 2 mm. I then set my belt sender table to the head stock angle and bevel the nut side about 10°.



I am finding I really need to take care when working on the neck with an ebony strip to make sure it is really level. The headstock was not! I leveled it with a block plane and not shown I used a sharp 3/4" chisel as a scraper.



With it level I clamped down a spacer on the nut location and glued on the head stock. I used a caul I have for my ukuleles and clam clamps





While waiting I thicknessed some braces with a block plane and braced the top and back. Not real hard with a ukulele





I trimmed the heel side of the top right to the profile line and used the cut off to set the depth of my router to cut the ledge for the top. Cut from the slots out so that the router spends very little time cantilevered out over the ledge.







Check the fit



I had a fretboard with 14.7" scale length so I profiled it and trimmer it to size










Check the profile and thickness to a bit more than 4 mm





I ended the day by rough profiling the neck and heel and fitting it and the top on to my work board.

John just now checking out this thread. That Tulipwood looks awesome, this little guy is going to be really good looking
I can't believe how small it is. With you hand there to give a real feel for the size. Great work as always.

Thanks Kevin,

Yesterday I got a bit of time in preparing to glue the rims to the top. First off I needed to straighten up the shop. It is amazing how quickly stuff piles up.



Luckily my work board provides me with a new surface I can work on.



I shaped all of the top braces. Nothing fancy the fans have little taper and rounded tops









I will play with the braces once the rims are glued on if I feel they are too stiff. First step is to align the neck and top and glue the neck to the top.



I get under my work board to check the neck center.



The neck and the top are glued on in line!





People following this blog might remember seeing that I had braced the back earlier with the top. Unfortunately at that time I did not think to radius the braces or glue them in a radius dish. I am putting a 25' radius on the back.

So I took a chisel and spit them off the back and cleaned them up. Thicknessed, put the 25' radius on them and glued them to the back in a 25' radius dish.









Profiled the back braces









This morning I got an idea to shape the volute on the -back of the head stock. I have a Luthier's Friend Sanding Station. I have been nervous using it to create the volute for fear of accidently sanding a divot before the volute. I have a roll of gluboost Master Shield Tape. It is to sanding what masking tape is to painting. I protected the planed surface with the Master Shield tape and then sanded in a 1" radius volute up to the nut line.





To get an idea of how it worked I rough carved the volute mostly using a carving knife.





It will turn out ok. I will wait until I have the fret board on until I finish shaping the neck.