Tuesday, 1 April 2014

A mold for an acoustic guitar - The Cavendish

A long term task I have set myself this year is to make a series of jigs and fixtures to produce acoustic guitars loosely based upon Jonny Kinkade's plans from his book "Build Your Own Acoustic Guitar". The one he outlines in the book is called "The Kingsdown".
Kinkade Guitars "The Kingsdown"

I have decided to call mine "The Cavendish"
The Cavendish will have my TMC headstock with the following specification:
  • Scale length of 25.5"
  • Body length 500mm
  • Body Depth: 105mm
  • Body Width of 385mm 
  • A thin flattened C electric type neck with a nut width of 43mm.
  • Neck radius 10"
  • The truss rod will be adjusted at the headstock and will be a double action type.

Mold construction

I set out converting a load of 25mm thick (1") MDF I had lying around the shop into a solid mold. First of all I laminated 8 sheets of MDF to make 2 glue ups 4" thick.

Each glue up was cut to size on the tablesaw and the edges jointed.
Next I made a symmetrical half template based upon his plans. I transferred the template onto the MDF laminate using a pencil. Then using the bandsaw I cut close to the pencil line. Then, using my oscillating spindle sander, the profile was smoothed, removing any saw cuts, to the pencil line.

Next the two halves were brought together and fixed with a fabricated bracket and thumbscrew arrangement. I drilled and reamed for 10mm dowels and glued the dowels in one of the brackets. I then smoothed the transition between the two halves on the OSS and with some sandpaper.


Next I made a template from 5mm plywood which I will use when cutting the sides of the guitar to height.
Routing the sides height template.
The Bessey Uniclamps are superb BTW.

The sides height template routed.
All will be revealed in a later post as to its usage.

Some oak brackets, dowels and thumb screws.
I glued and screwed the brackets to the MDF rather
than rely upon the glue bond alone. MDF is a bit
like paper and will tear with moderate pulling force.

The two halves of the mold

The mold complete.
The corners were cut off to make the mold lighter.
 Note the labelling.

I have just put the templates and mold into the rafters in my shop until they are required.

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