Top and Back

Most tops and backs are book-matched (re-sawn from the same board and opened like the pages of a book). Some builders of smaller instruments use a single piece, but I like the symmetry of a book-matched top or back—particularly when the grain has a nice pattern.

Spruce has been the traditional wood of choice for guitar-family instruments, but ukuleles are an exception. Mahogany was used for the entire instrument in Martin ukuleles (I've still got a Martin soprano ukulele I got when I was eleven or twelve years old). Ukuleles made in Hawaii have tended to use koa, a wood similar to mahogany, but with sometimes striking grain patterns. Many other woods may be used, but tops are usually softwood, while the back and sides are usually hardwood.

My first hand-made uke was made mostly from wood available at my local Home Depot. I chose hemlock for the top (Home Depot doesn't carry spruce, but hemlock is a somewhat similar evergreen softwood). The back, sides and neck were of poplar. Home Depot offered no other hardwood except oak, which looks good in furniture and cabinets, but is not really suitable for musical instruments.

I needed a hardwood for the fretboard. Traditional woods are ebony or rosewood, neither of which was available at Home Depot. I raided my firewood pile for a piece of locally grown black locust.

Two sets of bookmatched koa (for tops or backs)

After the wood for the top has been cut into properly book matched pieces, it is planed and sanded to a little thicker than its final thickness. The edges that will be joined together are carefully trimmed so that they join perfectly, with no gaps. Then the two pieces are glued together. The traditional glue for stringed instruments is animal hide glue. Some builders still use if, but more (including me) use a carpenters' glue such as Titebond.

After the glue dries, the new piece can be lightly sanded to "true up" the glue joint. Then the center of the sound hole is marked and a pilot hole is drilled. The pilot hole is placed over an indexing pin in a workboard I use for routing the groove that will later receive the rosette.

Koa top with rosette in place

Rosettes serve a dual function: they are decorative, and they also reinforce the sound hole to prevent splitting. I make mine from thin acrylic bordered with plastic strips called purfling. The rosette is shaped to fit the slot as exactly as possible—and it's just slightly thicker than the depth of the groove that was routed earlier. After the rosette is glued in place it can be sanded flush with the top's surface.

Carving the top braces

The next step is to turn the top over and glue the braces in place. There are two transverse braces—one above and one below the sound hole. The lower bout has a patch or "graft" of thin reinforcing wood in the area that will support the bridge. Three "fan" braces help prevent warping that might happen as a result of the string tension on the bridge. The braces have to be strong while being as light as possible. The grain in the wood needs to run vertically for strength.

Back with braces and center graft

The back is made very much like the top, except that it has no sound hole and the bracing scheme is different. The back has three transverse braces which (unlike the top braces) have a slight arch. There's also a patch (graft) of cross-grained wood that covers the center seam.

Side Bending

Re-sawing

The sides start out as book-matched pieces of wood about 18 inches long, three and a half inches wide and less than an eighth of an inch thick. A nicely-grained piece of wood is resawn on the bandsaw to make the two book-matched pieces.

I put them through the thickness planer and then through the drum sander to bring them to the appropriate thickness.

Finally, they need to be bent. This was the scariest part—until I tried it! Side bending is accomplished with a combination of heat and moisture. Heat relaxes the internal cell structure of the wood, allowing the cells to slide past each other and change shape. The moisture is only necessary to keep the wood surface from burning. If the bending apparatus doesn't get too hot, the water is not actually necessary; however, a little higher temperature speeds the process.

Home made hot pipe (heat comes from a charcoal starter)

Side bender in use

I use two bending tools: a heated pipe and a side-bending form. The hot pipe is heated by means of an electric charcoal lighter connected to a light dimmer switch. The dimmer allows me to control the temperature of the pipe (which should be between 300 and 400 degrees Fahrenheit).

A ukulele side has three bends: the upper bout, the waist and the lower bout. I bend the waist first, using the hot pipe, and then transfer the still-wet side to the side-bending jig to complete the bends for the upper and lower bouts.

It's possible to make all the bends by hand using the hot pipe, but the bending form saves time and helps produce uniformity. The bending form is heated by two 100-watt light bulbs inside. As the wood heats, I gently bend it to follow the form, and clamp it into position. The heat stays on for another 15 minutes or so, and the bent side stays in the form until it cools. Occasionally it needs a second session of heat in order to maintain the proper shape.

Wood

Tradition rules. Many luthiers (stringed instrument makers) strive for something new and different, but "tried and true" got that way because it works. There's always room for personal touches, but when it comes to basic design, as well as the choice of woods, the beginning luthier would do well not to branch off into uncharted territory.

My plan was to use my Stewart-McDonald kit as a pattern. I had also purchased a book (Ukulele Design and Construction, by D. Henry Wickham) which included full-sized plans. Now I had to select the wood.

Part of my wood collection

Different woods are used for the uke's different parts: top, back, sides, neck, bridge, interior bracing, and decorative parts such as inlays and laminates. Ukuleles have traditionally been made entirely of mahogany, with a trend in recent years toward koa (a Hawaiian wood similar to mahogany, but with more beautiful grain patterns). Spruce is the traditional choice for tops in larger instruments, such as the guitar, and is also popular for the larger ukulele's, such as the tenor, concert and baritone. Backs and sides are made from a variety of hardwoods.

Morado (the long one), bloodwood, rosewood and ebony

Since I was trying to stay with wood I could buy at the local Home Depot, I chose hemlock (an evergreen softwood something like spruce) for the top. For the neck, backs and sides, I chose poplar—the only hardwood available, except for oak, which is usually not a good choice for instrument making.

The fretboard is traditionally made of a dark hardwood such as ebony or rosewood. Home Depot offered neither, so I looked in my firewood pile and found a piece of locust that I could saw into boards. I used locust for the bridge, and I had a piece of walnut that I'd saved from a tree my great-uncle had cut down years ago. I used some of the walnut to make a thin veneer for covering the headstock (that's the part where the tuners are).

Tools

Before you can begin building instruments, you need some tools and equipment. I already had a good assortment of woodworking tools, but one thing that's essential is a way to create thin sheets of wood for backs, tops and sides. Imagine a sheet of wood that's thinner than a slice of cheese and maybe as big as a single newspaper page. It's possible to hand plane such a piece of wood, but power tools make the process much easier.
I already had a thickness planer.

Rigid 12" thickness planer

 It's able to take wood down to an eighth of an inch (even thinner if you put something under the wood as you run it through) but the planer uses rapidly rotating knives to thin the wood, so if the wood is too thin, some tearing (or worse) might occur). That's why I needed a drum sander.

Home made drum sander

A drum sander has sandpaper wrapped around a rotating cylinder (drum) and a mechanism to regulate the distance from the drum to the feed table. Drum sanders are expensive (I eventually bought a commercial one, but wasn't ready to invest the money at this initial stage), so I made my own—as an attachment to my wood lathe. The table was an old piece of counter top fastened to a base with a piano hinge. I devised a cam lever to raise and lower the table. The drum is a piece of ABS sewer pipe with wood blocks in the ends. It's clamped between the lathe's centers. Sandpaper is wrapped around the drum and secured with nylon wire ties.

Craftsman bandsaw

Several more power tools are important:  a table saw, a bandsaw, stationary belt sander and a drill press. I also have a Delta scrollsaw and a wood lathe, as well as a Jet drum sander and the usual assortment of powered hand tools. The bandsaw allows you to cut curves, and it can also saw a board into two thinner boards (called resawing). It's important that the blade guide can be raised high enough to resaw a board half as wide as the finished width of the instrument you're making. Tenor ukuleles are about 9" wide at the widest point (called the lower bout), so the bandsaw would need to resaw a 4½” board. Mine handles widths up to 7½".

My drill press is used for many things besides drilling. I cut the soundhole in the instrument top using a fly cutter. I have several, all preset to specific dimensions. I also have an assortment of small sanding drums that are invaluable when shaping necks.

Shop Fox stationary belt sander

The stationary belt sander I use is made by Shop Fox. There are many stationary belt sanders out there, but this one easily converts from horizontal to vertical, making it a good edge sander. I also allows me to make use of the end rollers to sand curves, and I've made a fence that turns the end roller into a small-scale thickness sander—very useful for small parts such as bridge saddles.

Lumberyard Uke

For years I had thought about building musical instruments. Guitars? Mandolins? Dulcimers? I wasn't sure. I had some experience repairing, and even rebuilding stringed instruments, but I had never made one from scratch. When I saw some hand-made ukuleles, I knew I'd found a good starting place. The smaller size meant a mistake might not cost me as much—and my existing tools would probably be sufficient.

I did some Internet research and discovered Stewart-McDonald, a supply house for instrument makers. I bought a tenor ukulele kit—along with a how-to DVD. My plan was to use the kit as a template for building my own instrument. What follows is a record of the creation of my first hand-made instrument. I call it my Lumberyard Ukulele because most of the materials came from my local Home Depot.