Archive for May, 2008

Top Bracing/Joining the Top, Back & Sides

 I’ve gotten a lot done in the past week and am a bit behind in the blog.  The fingerboard is almost done and the neck has been made and needs shaping and purfling.  It’s coming together quickly.  It goes in the spray booth next week.

The first photo below is the obligatory “luthier carving braces” photo. I’ve shaped the back braces using a couple of those little planes I have and a sharp chisel and am cutting the ends of the braces down to 3/32 to get slotted into the kerfing.  All the trim that runs vertically needs to be installed before I rout the binding ledges.  This includes the end graft (below) plus the trim around the point of the cutaway and the joint next to where the heel of the neck meets the body.  I’ve opted for very minimal decoration on the guitar and will be using koa binding which will look really neat against the rosewood.

 The next photo shows the side braces being installed.  The sides of the guitar are very thin and are prone to cracking, usually when you’re resting the guitar on your leg and something hard (like your keys or change) press against the sides.  These help minimize this.  After that I routed the slots for the braces and glued on the back.

Finishing the back End Graft Side Braces 

While the back is setting up I’m back to the top.  I cut the rosette using a Dremel tool and a really neat little router base that Stew-Mac sells.  The router rests on a pin stocking out of a piece of plywood (first photo).  The router then just pivots about this point and cuts the channel.  The trick here is to go slowly and using climb cuts most of the time.  I’ve chosen a narrow band of paua abalone shell (abalam, actually) edged with fine black and white purfling.

After that dries I plane the purfling down and then level the rosette using the drum sander.  Now it’s ready for the braces.  I transfer the pattern from a plan to the backside, then use the jig to cut out the soundhole the rest of the way.  Braces are shaped in the radius dish just like the back (30 feet this time, though) and glued to the top using the go bar deck.  After final shaping and sanding I glue on the saddle plate and the fretboard extension support block at the top of the last photo on the right.  This helps transfer the tremendous forces laterally to the big transverse brace right below it.

Rosette Jig Routing the rosette Rosette Transfer the pattern Gluing on the braces Top, signed and ready to go

Back in the Go-Bar deck.  A few hours later the guitar can be removed from the mould.  I use a flush trim bit in a router the trim the top and back.  Now it’s ready to be bound.

Gluing the top in the Go-Bar deck Body, ready for binding

I’ve skipped a lot of the small steps and sometimes the order of things is slightly different.  I usually have several things going on at once and am moving back and forth.  I’m also building three guitars at the same time so it gets confusing.  If you have any questions about what I’ve done feel free to email me if you don’t wish to post them publicly and I’ll be happy to get back to you.

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