Braces

I rough out the back braces out of 1/4" sitka brace stock with the bandsaw.  The curve is a 15' radius.  Then I perfect the curve by sanding the braces in a sanding bowl that has the same 15' radius.  Later, I will take a small, very sharp plane to make the bottom curvature of the braces exactly square to the sides.  I want the glue joint of the braces to be perfect, since the braces are so narrow and fine, and old guitars often suffer from detached braces.

The back will be bent to the braces when gluing.  In this way the back takes on a perfect 15' arc.  Similarly, the top is caused to adopt a 25' radius.  The curvature helps sound projection, but also makes a stronger box, since an arched back and top creates stronger shapes than flat panels.  In the bottom picture, you can see that the front braces have the nice curvature conforming to the sanding bowl, and the rear, unsanded brace is about a centimeter above the middle of the bowl.

More Work on the Back

The outside of the back.  The outline has been cut on the band saw.  The cut is a little big - the excess will be trimmed with a small trim router after being attached to the sides.

The center strip glued over the center joint.  The back is two pieces of book-matched rosewood.

The braces will be freed from this piece of well-seasoned brace stock.  It has been in my shop for about three years.  It is Sitka spruce and is very densely/tightly grained, perfectly quartered and with no run out.  Braces are most important.  Strong, light and without flaws of any kind is necessary in order to work properly.  Light so as not to weigh down the plate to which they are affixed.  Strong to resist deformation with about 200 lbs of tension from the strings.  And no run-out to ensure that they will be strong in 50-100 years.

Indian Rosewood Back and a Secret

The back is planed to 0.085".  Notice the Indian Rosewood center inlay and purflings.  This instrument will be subtle.  No flashy pearl or paint or wacky pick-guards.  The wood is the thing.  This rosewood is chocolate brown with purple and tan.  This will be wonderful under finish.  The tool shown is a Lie-Nielsen scraper plane.

The "secret" inlay.  Some herringbone in the tailblock, where it will live inside the guitar.  Where it can't be seen without foreknowledge and a mirror.  There will be more secrets, too. 

The neck is mahogany, with a maple center strip and thin flanking strips of something darker.  I can't remember what right now.  Lots of finish shaping to do but it is close to the right overall dimensions.  Final working happens after the neck is fitted to the body and the angles are established for the correct saddle height.  A long process with a tolerance of about a 64th of an inch.  If the saddle is too low, there is not enough leverage on the bridge and the instrument is too quiet.  Too high and the saddle might break out of the bridge or pull the whole bridge off the top.  It's all about sensing the balance.  Listening to what the wood tells you.

Cyclocross Nationals 2012

Katie Compton (#1) at the start of the Women's Elite

Katie soloing in for the win - Women's Elite

Amazing crowds - at the run up

Eventual winner, Jeremy Powers (#2), in the front group waiting for the right moment - Men's Elite

The Sides are Bent and Lined

Bending the sides to fit into the mold

Gluing in the neck block after the sides are bent

Sides bent and in the mold, neck block and tail block glued in and spreaders in place

Sides are sanded in correct curves - back is 15' radius and top is 25' radius

Gluing in the reverse lining, slightly proud - reverse linings are stiffer than conventional kerfed linings

Now we sand the correct curve into the linings using the correct sanding bowl until the linings have perfect dome shape to receive the top and back

Sides are done - planning some hidden inlay work for the tail block and reinforcing strips which will be added after the glue dries for about a day

Karen at the Botanic Garden

One of our all time favorite places, the Chicago Botanic Garden, where we did a bit of walking last weekend.  When it's cold, the greenhouses are particularly soothing.