Mandocello - Projects - Audio Artillery

Mandocello

  1. Intro
  2. Design
  3. Top plate carving, exterior
  4. Top plate carving, interior
  5. Body construction
  6. Side bending
  7. Neck construction
  8. Headstock
  9. Body construction II
  10. Bracing
  11. Neck joint
  12. Back plate
  13. Body assembly
  14. Neck, meet body.
  15. Neck shaping
  16. Tailepiece
  17. French polishing
  18. Finished

11: Neck joint

This will be a straight mortice and tenon joint with barrel nuts bedded into the tenon and bolts used to secure the joint. I got this design from Graham McDonald's GAL bouzouki article.


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Once the initial cut of the tenon fits into the mortice the corners of the tenon must be relieved bit by bit until it fits the contour of the neck block.


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These are the fasteners that will be used to bolt the neck in place. They are stainless 1/4-20 bolts with a type of captured nut (can't remember the name). You can find this sort of stuff at McMaster-Carr in small quantities.


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The bolts poke thru the neck block and will later thread into the captured nuts inside the neck tenon.


 

12: Back plate

Same process as for the top plate.


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I did a better job with the angle grinder, resulting in a lot less material to remove:


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By this point in time I had a cheap set of scrapers. These work better than the rasp thing I was using.


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13: Body assembly

I used an odd strategy for gluing the top to the body. I don't have a way to clamp the whole top at once so I glued just the neck block area first, then one side, then the other side. I used a putty knife to shove the glue into the unglued areas. I read that this is a common way of gluing cello tops.It works well enough. Cedar is flexible and the top was bowed upwards anyways (just from the carving). It's hard to get really thin, consistent glue lines with this method though.


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This is my solution to the clamping problem. The form is inside to keep the rough shape. Nails in the top's edge allow me to use rubber bands for clamps since I don't have that many large clamps. But be careful, I clamped too hard on one are and the side wrinkled up under the stress. The extremely thin sides may have something to do with that.


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This is a simple base for my router to let me route around the edge of the plates. It worked great. I had one spot where routing against some end grain caused some minor tearout; I switched to a higher speed on the router and that seemed to fix that problem.


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The side material is thinner than I intended. I noticed some buckling when clamping the top and figured some reinforcement would be a good idea. These small strips ought to prevent any splitting or buckling.


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I was smarter by the time I got to gluing the back. I've fabricated a couple dozen of these cheap clamps (not my idea, I've seen this many times elsewhere) from a 1" poplar dowel, a few 1/4-20 threaded rods, and a handful of T-nuts and wing nuts (you could just use wingnuts). They work great.

I also wisely put the plate being glued on the bottom so that the squeezeout wouldn't run down the sides and make a lot of cleanup work for me.


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14: Neck, meet body.

Here is the roughly shaped neck with fingerboard extension glued on and the whole assembly bolted to the body.


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15: Neck shaping

One of the many benefits of a bolt-on neck is you can bolt it to anything you want.


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The actual shaping was done mainly with a block plane and spokeshave. The fretboard area was also flattened prior to gluing the fretboard. This should be an easy task with a jack plane but the complicated neck construction lead to there being [i]five[/i] grain directions from the different pieces of wood.

Once the sides of the neck are tapered correctly the fretboard can be attached. The below caul was made from a flattened 2x4 and some 1/4" dowels that were glued on and then also planed flat. This gives something solid to clamp on and prevents the fretboard from curling up around the edges as they can do when absorbing the moisture from the glue. Got the caul idea from some helpful mandocafe board member.


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Another glue-up trick not shown in the pictures is the use of two locator pins that I installed in the fretboard that fit into holes in the neck. This allowed me to align the fretboard perfectly at glue time and keep it from slipping around while I clamped it. I used 1/16" brass rod for the pins.The fretboard is then planed/scraped to shape. I'm using an Maccassar ebony from LMII with a 9" radius.


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