American Lutherie #113 cover shows a mandolin scroll being bound in ivoroid in the shope of Andrew Mowry.

American Lutherie #113
Spring Issue 2013
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Page 20 - Bog's Way - An In-Depth Hands-On Review of John Bogdanovich's Making a Concert Classical Guitar DVD Set by Tom Harper

The plans for the instrument include a drawing of the side profiles used to trim the sides to a nominal shape. Since my body shape is a little different than the plan, I needed to make my own. I use a method of side height calculation that Mike Doolin wrote about in AL#75. The photo shows the setup I use to get a set of x,y grid points evenly spaced around a side. The rulers are held perpendicular by the square so the x,y locations read off the rulers are accurate. The tape attached to the template has tic marks drawn on it every centimeter. An inch would suffice, but nothing exceeds like excess. The tic marks define the x,y location on the grid and are transferred to the paper. The rulers are used to read off the x,y coordinates for the transferred tic marks. Doolin’s method (math compliments of John Sevy) uses these points to calculate the side height at the points assuming a dome shaped back or top. You can use the results to cut the sides to shape before bending them. I did not cut the veneers for the sides to shape before bending them because I was worried about adequate bonding at the edges.
Another shot of the makeshift lining mold. Another shot of the makeshift lining mold.
The sides are trimmed to nominal shape using an outline from the plans. Once the sides are marked, a saw is used to make the cut. I attempted to make the cut resting the side against my workbench, but discovered there wasn’t enough support. Bogdanovich’s woodworking bench has an end vise that creates a gap to securely hold the side. I did my best to mimic his end vise with my Parrot vise. It was better, but still a bit difficult. Note the spacer on the left to create the gap needed to be able to move the side around as you cut.
The side/lining assemblies fitted into the solera. The fit is still excellent with little variation between the outside molds and assemblies. These sides are very rigid.
Checking the lengths of wood for the heel stack. Normally, longer pieces make the job easier. I had a piece of mahogany that was just the right length with nothing to spare and like a fool, I used it. It worked, but there was no room for error. You can see the one of the printed out plans under the neck wood.
Getting ready to glue a lining to a side. There is a piece of double sided tape at the waist that holds the caul in place.
Marking for the side slots in the heel of the neck. The mahogany is kind of grainy, so it’s easier to see the marks if some tape is attached to the wood.
Bending the wheat element into shape requires successive heatings. This little form helps keep it circular as you dial it in.
The first strip of herringbone is inlaid into the top. Only the necessary width of channel for this rosette element has been cut, and subsequent cuts are made for each additional element. It is important that there is no slop in your router circle cutter setup, including the hole size for the pivot pin. I used two pins so I could leave them in place on the top and the test scrap.
Gluing in the wheat. I am using a round piece of plastic to press the wheat down into place.
Bogdanovich does not use vacuum in the course, but I have it and was feeling lazy. I’ve gone from a vacuum form with a lid to a bag which seems a little less fussy when it comes to holding a seal. The bridge patch is being glued in place. Seems like a lot of stuff to glue a small piece of wood in place, but it’s fast to set up.
Bogdanovich prefers to trim the braces to a parabolic shape before gluing them in place. I usually glue, then trim, but gave this a try. After 15 years of doing it my way and doing it his way once, I kind of prefer my way, but not strongly.
Bogdanovich uses cam clamps to glue braces on. I really liked it, but don’t own enough clamps to glue the long braces down. The pads on the clamps keep them from denting the braces even though they are already carved. The braces also stay put once the clamps are in place.
The shaped back braces ready to glue in place.
Starting to put the string slots in the headstock. The idea is to quickly remove most of the wood using a drill followed by some cleanup with a chisel, then use a router guide to finish it up. Removing most of the wood before routing makes the process go faster, but more importantly, minimizes the risk of tearing something out when routing commences.
Here are the slots and roughed out headstock shape. Now it’s time to clean up the shape with chisels and files. I’ll attach the headstock template with double sided tape for a guide.
Wow, this $10 Fast Fourier Spectrum Analysis software running on my Nexus 7 seems to work pretty well! I have found that working the top to achieve a more even response across the spectrum seems to create a better sounding instrument. In the past, I’ve used expensive software that needs updating, but I think I’ll continue to try this less featured, but lots less expensive program. For this instrument, I followed Bogdanovich’s guidance and did not make changes based on the software’s output. You can also see the way the solera creates the tilted domed lower bout area in this photo.
The headstock shaping is starting to come into form. My curved ramps did not come out as nice as what Bogdanovich achieves, but I am happy with the results for a first time effort.
The sides have already been attached to the neck and the interior tailblock has been glued in place. The top is being checked for a good fit before gluing the top to the assembly.
David Hurd’s book “Left Brain Lutherie” discusses deflection testing. This is my setup that collects the data used to make a compliance map. Compliance maps are essentially topographical maps that show the contours of each deflection amount. I find that if I can create a map the has nice round contour lines like a circle or ellipse, rather than areas that have s-curve contours, the instrument has better sustain and focus. I did not use this information for changing the top stiffness because I wanted to follow Bogdanovich’s voicing guidance. I plan to play the guitar for awhile, then if I think I can improve on my initial voicing efforts, apply my methods and hear what happens.
Letting the back braces into the linings. Bogdanovich marks the locations, then cuts with a small precision saw, and cleans up with the chisel, as shown here. The back is a bit oversize, so there is a little room for error, but careful measuring makes for a clean looking inside view once the back is glued on.
This is the result of sanding the sides with a 15-foot radius domed sanding board in preparation of attaching the back. The solera and outside molds provide enough stability that the dome can be used freehand. The neck is clamped to the solera to hold it firmly in place.
The sides have been sanded to the correct radius, the back brace slots have been cut into the linings, and the back strip has been carefully cut to length, so it’s time to glue the back on. This is beginning to look like a guitar!
The instrument is in position to begin the glueup. The solera design includes a stiffening bar on the bottom that can be used to clamp the solera in a vise. Holding it in a vice makes it easy to perform tasks like clamping the back to the sides for gluing.
The neck shaping starts with some rings that are correctly thicknessed and shaped at either end of the arm. The rest of the neck is worked down towards the rings with successive refinement of curvature.

Page 45 - D'Aquisto Wedge Bridge by John Monteleone

   

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