Classical Guitar Update

I finally got the neck blank constructed and the sides bent without ruining them:

Here's the back with braces being glued and after I arched, scalloped and sanded them:

Bender update

I practiced bending using the new electric heating element last night, and the pipe did eventually hit 300 degrees. The 1.8mm Jatoba I was bending actually started to lightly scorch, so I suspect the temperature would continue to climb.  It is a very slow rise and the temperature remains much more consistent than with the torch. In case you're wondering, I'm using a Char-Broil  Electric Charcoal Starter inside a 3.5" OD copper pipe, which is about 12" long. I bent the heating element in a wooden-jaw vice until it fit, just touching the inside wall.

Classical Guitar Update

Over the weekend, I finished the neck scarf joint and glued up the back with the maple back strip. I cut the scarf on my bandsaw by clamping a 90 degree block to a miter guide and then clamping the neck blank to it for the 15 degree scarf. Next, I clamped the short piece to the long such that they formed a smooth ramp and sanded the joint surface clean on a belt sander.

The back plate came out good but needs to be thinned down a bit more. 

I'm still having hell bending sides. I ruined two sets -- Jatoba and Mahogany. I tried fabric softener on the Mahogany, as suggested by an experienced luthier, but that only seemed to make the wood rubbery and wouldn't retain its bent shape. I think I soaked them too long and they absorbed enough water to swell to > 2mm thick. Next time I will start out thinner.

Anyway, it turns out that Mahogany is one of those woods that you don't want to soak because it can cause compressed fibers. So much for taking an experienced luthier at his word.

I got tired of the propane torch for the bender because it isn't adjustable and gets too hot, so I bought a cheap electric charcoal starter for $10 at Lowes and compressed it to fit into my pipe. It heated the 3.5" copper pipe outer surface to about 270 degrees and stayed there consistently. That's not quite as hot as I would like, but I was able to dry bend some mahogany pretty easily.  Inside the pipe was 600-700 degrees, so I may be able to get it hotter. It seems that you still have to keep the sides at or under 2mm.

DIY fret tang nipper for $7

While I was browsing the Stewart-McDonald catalog, I noticed their fret nipper tool and realized it was just a modified nibbler. So when I found a nibbler at Harbor Freight (#97636) last weekend for $7, I couldn't pass it up.

I bought the nibbler and filed a 1/16" recess tangent to and just above the cutter so that half the crown fits in the recess and the tang is flush to the plate. Squeeze and presto - tang is gone cleanly.

Now, if you're wondering what this is all about, it's so that the fret tang doesn't interfere with fingerboard binding.

Stewart-McDonald goodies! Yay!

I haven't ordered from Stewart-McDonald since I was a teenager. Now that I am building guitars again, I needed a few items to complete my two classicals and decided to buy a few toys. I went ahead and ordered the precision router base set, which is quite nice:

I also ordered the circle-cutting jig, but it arrived damaged :-( Apparently the brass bushing that the center pin goes into was crushed during assembly. I called StewMac this morning and they are sending a replacement.

Current Projects Update

Well, the wife has reprioritized my projects, and my guitars got bumped. My daughter really needs her own room now, but she will have to move to a smaller one, so my wife wants me to build her a loft-style bedroom suite.

1. Loft bed, desk and dresser for the daughter
2. Two classical acoustic guitars
3. Bunk bed for boys
4. Towel rack for the kids bathrooms

I really like this craftsman-style suite, and I already have the plans, but I need to figure out how to convert the lower bunk into a loft support (while still possible to separate) without weakening the structural integrity.

Bracing glued and trimmed

I got all the fan braces glued and trimmed - just finishing up the V-brace. Next I'll glue the upper and lower cross struts and upper transverse bar. The fan braces were much easier than I anticipated. I marked the outline of the bridge graft with a pencil and cut them with a chisel. After they were glued, I shaved them down with a block plane, then used a chisel to scallop the ends. Interestingly, I started scalloping with a gouge but found that a chisel with the bevel down worked much more efficiently. Finally, I sanded the everything with 220 garnet paper.

 

Grafts glued

Here are the grafts glued up after I cut out the and sound hole:

Rosette Inlayed

I got the rosette channel cut last night and spread a little shellac around it. This morning I glued in the rosette. Hopefully this evening, if everything worked right, I can smooth it out and start gluing the bracing.

The rosette inlay turned out great. I was able to scrape it down and I will start bracing tonight.

Router Circle Cutting Jig

After my last post, I decided to replicate the Jasper 400 for my router base plate using 1/8" hardboard. The reason I chose to make it versus buying the Jasper is 1) I need it now and 2) the reviews on the Jasper indicate that it breaks easily--not acceptable for a $30 tool. The advantage over it instead of using the edge-guide compass conversion is a smaller footprint. This design is essentially what is described by Cumpiano in Guitar Making: Tradition and Technology.

Well it turns out that even this footprint is too large. While the router gives excellent depth control, the weight results in greater risk of damaging the soundboard surface. I really like the base and jig from Stewart McDonald, but I don't want to pay $100+ for them. Back to the drawing board...perhaps I'll machine one.

UPDATE: I finally caved and bought the router base from StewMac. It's excellent, btw. Even considering the price.

Convert a Porter-Cable 42690 edge guide into a micro-precision router compass

I needed a circle-cutting router guide to cut the recess for the rosette in my soundboard. At first I tried the compass that came with my Rotozip, but it was too floppy. Next, I built a compass for the Dremel router base edge guide, but the depth control was unreliable. I considered buying the Jasper 400 Circle Cutting Jig, but after looking at the design for this compass jig, I decided to convert my Porter-Cable router edge guide into a compass jig by replacing the removable edge guide with a flat plate. Using the edge guide as a template, I traced the outline onto and cut the plate out of 1/8" hardboard, then drilled matching holes. I also drilled a 1/8" hole on the opposite end for the center pin. I reassembled the guide and attached it to the router. To mount the router flush to the plate, you have to remove the plastic base plate on the router. Once mounted, I extended the arm to cut the slot, but it turned out sloppy. The pin/nail must sit flush with the top of the guide plate and there shouldn't be any slop in center hole as it rotates around the pin. I am considering to remake the plate with 1/8" aluminum, but it's not necessary.