Monday, July 7, 2014

Flat Top Tele - Shipbuilding

It's just a rumor that was spread around town
A telegram or a picture postcard
Within weeks they'll be re-opening the shipyards


Some would say that bending sides of an acoustic guitar are a lot like shipbuilding, but with fewer parts, people and melodrama.  Like the underlying structure of a wooden ship, the guitar sides plus end blocks and linings are referred to as ribs.


Like building a concrete wall, it is necessary to build forms that are the negative, or outside, of the shape of the guitar sides.


Because of the complexity of the angles and curves of a guitar, as well as the tendency for bent wood to return to its unbent shape, it is common practice to use forms that sit inside of the guitar body when forming the sides, and another set of forms that sit on the outside of the guitar body when attaching the linings and the front and back panels to the sides.  Below are sketches I made while designing the form work for the Flat Top Tele.


Most modern manufacturing processes make use of CAD/CAM to produce highly accurate machines parts to close tolerances from scaled computer drawings.  With so much free information on the internet, finding a free, printable scaled drawing was quick and easy.  CAD/CAM technology is beyond the modest means at These Old Guitars at this time, so I used a tried-and-true manual method to make a tracing of the Telecaster body shape.  Starting with a full-sized plot, I applied a layer of graphite (aka pencil lead) to the rear side of the plot.  After taping the plot down, I used a stylus to transfer the outline onto a 3/4-inch MDF board.  To make it easier to see the outline on the MDF board during cutting, I drew over the pencil line free-hand with a marker.





The inner and outer forms I cut from the first MDF board served double duty as both forms and templates for the other forms.  I attached pairs of forms to each other and clamped the pairs together before shaping and sanding, so the forms would end up smooth and with matching curvatures.



I added some 2x3 blocking between the MDF side boards of the interior forms and a layer of 1x6 between the MDF side boards of the exterior form to get the proper finished form widths.  I used some wood filler on the outer forms to get a smooth, continuous surface.  Some additional parts including some PVC piping were sized and made ready, to be used to hold the bent wood against the forms.



With the inner and outer forms fully assembled, I warmed up my steam box and prepared my work areas for some wood bending.




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