Friday, December 9, 2016

How to make an experimental acoustic string instrument














I wanted to make an instrument using the lathe. So I came up with this 3 string instrument which I call a hybrid of a Greek bouzouki and a banjo. I made it out of spruce.

The body of the instrument is actually a segmented  bowl. For 12 segments I need 15 degree miters. 

I cut the miters on my table saw, using my miter sled.

I then sanded the miters on my DIY disc sander for the lathe.

I used blue tape and rubber bands to hold the miters while the glue set.

For the body’s bottom I glued a few pieces together. I also glued two pieces of wood for the instrument’s neck.

After the segmented ring was dry, I sanded it’s edges on the disc sander. I used the bandsaw to rough cut the bottom to size and glued the ring and the bottom together.

I then mounted that piece on the lathe with a face plate and turned it round.

To fill the gaps I applied glue and then sanded over that. This way the gaps were filled with dust and glue.

I glued wood blocks to the bottom. This way I have a little more meat for the neck’s joint and also my structure became stronger.

I then used my bandsaw again to rip a few thin boards. I grain matched them. To joint them I used a piece of sandpaper on a flat plexiglass. This way I sanded them flush and then glued them all together.

I rough cut the top on the bandsaw. Using a hole saw on the drill press I created the sound hole. I also glued a brace under the top for support. I shaped the brace with a sharp chisel.

I then created two flat spots on the body using the disc sander. I glued the top and the body.

I cleaned up the neck with a hand plane. I trimmed it to size on my table saw. For the cross cuts I used my sled and for the rip cut I used the fence.

I then cut the basic shape of the neck on the bandsaw. 

The neck is glued on the body with a dovetail joint. I shape the male piece of the dovetail on the neck. I made two stop cuts with a saw and a miter box and then shaped the rest with a sharp chisel.

Using a spoke shave I rounded over the back of the neck. I then sanded the neck. To shape a few difficult areas I used a sanding block as a rasp.

I then drilled the holes for the keys.

To make the female dovetail on the body, I made a few parallel cuts with the saw and then chiseled out the rest of the material.

I glued the neck and the body.

To make the fretboard I need the scale length. My scale is 52cm. I went to an online fret position calculator and printed out the measurements of my fret board.

I then made the fret slots using a miter box and a saw. 

For fret pins I used bamboo sticks.  I also used two pins to avoid the slipping of the fret board during glue up. I glued the fret board in place. 

I then glued the rest of the pins in place and cut them flush with my flush trim saw.

For the side fret marks I just burned a few points.

I used a cutter to cut the frets to size. Using a clamp I pressed the frets in place. To secure them more, I applied a few drops of super glue in the fret slots.

I rough cut the frets to size with a rotary tool and a cutting disc. I sanded them flush with a sanding block.

I finished the instrument with a spray acrylic clear varnish. I applied 5 coats while light sanding between coats.

Using my angle grinder, I cut a metal piece to act as string holder. Using a screw driver as a guide, I used a hammer to bend the metal in place. I made the the holes needed on the drill press.

I cut two ( plastic ) bone pieces for the bridge and the nut on the bandsaw. I shaped them on the disc sander. 

I clamped them on my vise together. I used a saw to make three cuts. Then I used a file to open up the holes that would receive the strings.

I cut a piece of iroco on the bandsaw to act as my bridge. I shaped it on the disc sander and cut out a groove to receive the bone.

I screwed the string holder and the keys in place. I added a couple of string guides and my instrument was ready.

I tuned it in D A D. 

I hope you like it!

4 comments:

  1. Para poly omorfo. Polla polla bravo.

    ReplyDelete
  2. παρα πολυ ωραίες κατασκευές μπραβο.
    τι ξυλα χρησιμοποιείς ;

    ReplyDelete