I’m currently building prototypes of the Appalachian dulcimers I will be producing.
First I come up with a concept of what I expect from the instrument.
I prefer an even response and voicing throughout the entire range of the instrument; every string at every fret should speak well.
There is a unique quality in the voice of a well made dulcimer that is both warm yet “hollow.” The tonal color is somewhat similar to a bouzouki or saz.
I also prefer an instrument that has a long, even sustain.
Dulcimers are a relatively quiet instrument. The basic structure of the instrument is responsible for both the tonal color and the lack of strong projection.
I have found that most attempts to make very loud dulcimers require compromising the tonal color I prefer.
I am building dulcimers that strike a balance between the preferred tone and a reasonable amount of volume. You can always use a microphone or a pickup to make an instrument much louder but it will only sound as good as it does when played acoustically.
Dulcimers also have some inherent structural problems that I correct during the design process. The long fretboard running the length of the instrument is prone to warping. This can cause problems with the action and intonation. The fretboards on my instrument are designed to be light, stiff and stay true.
Lumber starts out as a tree, usually a big tree if it is harvested for woodworking or instrument making.
The sawmill will yield boards from the log of reasonable and workable size.
Once the wood has been dried the craftsperson will resaw the wood to the dimensions needed for the work at hand.
These days this is most often done with a bandsaw. A standard 14″ bandsaw can resaw most anything an instrument maker needs.
The principle is pretty simple; a fence is attached to the table and the wood is held against it while being fed through the blade. The result is thinner slices of wood.
Setting up the bandsaw and fence is critical to the process but once everything is tweaked and set up properly I find resawing to be a relaxing process. I try not to get too relaxed as bandsaws are also used by butchers to cut meat…..
The one drawback of resawing with a bandsaw is the noise; it can get loud at times.
Before power tools were invented the traditional methods of resawing worked very well. This process takes longer and requires much more skill.
For large pieces of wood usually two people will operate the saw. This method of resawing is still in use today around the world.
I love to thickness tops, backs and sides with hand planes. It’s quiet, challenging and a good physical workout. If all goes well the surface of the wood will be just about ready for finishing.
That being said, to produce instruments for sale in a reasonable amount of time most luthiers will use a thickness sander to prepare the wood.
I decided to give this a go but I didn’t want to invest a lot of money on a machine nor did I want to add a relatively large item to my small shop.
Until recently commercially available thickness sanders were large and expensive. Many instruments makers cobbled their own machines together. Though smaller and more affordable thickness sanders are now available I decided to make one out of what I had lying around.
The heart of most homemade thickness sanders consists of a drum sander spinning over a hinged board. When one end of the hinged board is raised the distance between the board and the sanding drum narrows providing an easy way to determine how much wood will be removed with each pass.
To make this machine I used a 1/3 HP motor salvaged from a cheap drill press destined for the scrap heap, some plywood, an old end table I was trying to give away, a 6 inch sanding drum and a few odds and ends from the local hardware store.
There is a knob on a threaded rod underneath the hinged board that doesn’t quite show up in the photographs. This knob makes it easy to open raise or lower the height of the table by small increments. The two brackets on the sides of the table keep it from wobbling from side to side. They work but if I was making this again I would use something more substantial.
The dust hood was made out of some scrap lumber and plywood. At first I just fit a shop vacuum hose into a hole drilled in the top of the dust hood. After the third or fourth time it fell out I screwed on a hose adapter and it works much better. The machine produces surprisingly little dust as long as the vacuum is running.
I use 60 grit sandpaper on the drum.
The sanding drum is mounted to the motor leaving the other end of the drum free. Using the 6 inch sanding drum I can sand a board up to 12 inches wide in two passes.
The machine works quite well as long as I take light passes. I leave the sanded wood a little on the thick side. I then vacuum and wipe off as much dust and abrasive as I can.
A few passes with a scraper removes any grit left behind and I do the final thicknessing by hand.
I’m currently working on a dulcimer in Cherry but I thought I’d get started on the next in line. That one will have Walnut for the back and sides and a Cedar top.
Here is some of the wood that has been up in the attic. This was resawn about a year ago.
I take what I am going to use and keep it in the shop for a few weeks so that it can get acclimated to the environment in which the instrument will be built. I keep the humidity in the shop at around 40%.
Here’s a two piece Walnut back that is about to be joined. The wood is sawn in two consecutive slices off the same board so that the grain is book matched. When joined the two halves will be a mirror image of each other.
To start I clamp the two boards together against the bench. There is a spacer under the two halves of the back elevating them a bit so they are within reach of the planes blade.
I then shoot the joint with a long jointer plane (for you old tool aficionados I’m using a Stanley #7 type 11 with a Hock A2 blade honed with a 10 degree back bevel.) For those of you who are not old tool aficionados (in other words, normal people) I’m using a long plane with a good blade sharpened and set up to take a very fine and smooth cut.
After the joint is shot true I edge glue the two pieces together using a few cam clamps. I weigh down the ends of the clamps to keep everything stable. I usually use a few planes as weights because they live right under the bench. I tamp down the joint with a mallet to make sure everything is lined up evenly and then I go do something else while the glue dries.
Does anyone else find this interesting? Let me know!