Post 8: Refining the Electric Cello design

    I started with that square 1"x 1" aluminum stick, but somehow could not see a flat cello with a low bridge. It would probably work just like the bass, but I need more excitement! 

   So I got the idea of cutting the stick and building the neck up. I received the ebony fingerboard from Amazon yesterday, and it's very well made and substantial. That allowed me to visualize things better., and draw the thing on scale. The three pieces will be bolted together with 2 long 1/4" bolts, and there will be a 1/8' aluminum plate attached on each side with 8-32 brass screws:

    I also collected information about the design of cello bridges and cello tailpieces, decided against a fine tuner, and finished the aluminum tailpiece, using a short length of copper braid as the tailgut held by brass screws and lock-washers. It will attach it to a brass rod crossing the square beam at an angle, ended on both sides with a 1" brass ball. The beam will be reinforced with a square chunk of solid aluminum, that will also hold the tail post:

        Then, I started with the scroll, trying to figure out a way to incorporate the decorative spiral piece of aluminum I happen to have. I have no idea what it was for, I just like it with the brass balls! I ended up with a pretty massive looking scroll made of two plated of 1/8" aluminum attached to the end of the square tubing beam. A short section will shape the end of the neck and increase the rigidity of the tuner box. The tuners themselves will be attached to pieces of 1/2" x 1/2" aluminum tubing. The helicoidal section of aluminum capped with brass plates and finished with brass balls will fit across the head through two 1 1/2" holes:

          I already had these chrome plated enclosed tuners, but I felt they didn't look right, and chose instead to order a set of bronze-colored ones that will compliment the brass and copper accents theme:

   

      Here is the basic layout of the whole full-scale instrument, in side-view. I have a traditional wooden bridge, but only as a guide and inspiration to designing my own and carve it out of brass, a 3/4 thick chunk of aluminum, and wood, incorporating a piezo pickup.:

      This is the kind of direct contact pickup I would like to use. Unlike the plain rod pickup, it is designed to be built into the bridge, and custom slotted to fit the strings Only, it is made for a bass guitar and is straight and inflexible.

       

     I just took it apart carefully. It is made of a steel channel, a 4 sensor piezo stick, and a piece of plastic divided into four sections to support the strings and act as a bridge. The plastic is hard and brittle and broke when I tried to bend it. I should have used the heat gun. Too late, so I broke it in four pieces, which will be glued to the four piezos sensors, and fit in a slot atop the aluminum bridge. The standard piezo stick I was going to use originally is shown on top:

    Finally, I designed a small decorative "body" inspired by a cello shape, to fit the 9"x 14" pieces of aluminum I had leftover. I drew it in pencil on the front view and just fiddled with the shape until it seemed right. The picture somehow makes it look bigger than it actually is:

         I am considering using a brass plumb bob as the endpin, possibly fitted with a brass ball... I have not decided whether to use little balls of small knurled knobs to keep the strings in place. 

        OK, time to build it!