Wednesday, November 24, 2010

Buy Now!

It's been a long time coming, but with the Australian dollar at last reaching parity with the U.S. dollar (and predicted to climb even further), the parcel delivery van has been an increasingly frequent visitor of late. With such a strong local currency at present, Australian exporters are feeling the pain, but as an importer of "must have" guitar-building tools and exotic woods, I'm in my glory.

For too long, as my finger hovered uncertainly over the "Buy Now" button on the Allied Lutherie or Luthier's Mercantile web sites, I was forced to add up to 50% to the advertised U.S. price as I made a rough conversion to my own currency - and that's before I'd factored in those truly horrendous international freight charges. Often, I'd indulge in a little harmless fantasy and fill my online shopping cart and then, after a moment or two to savour the experience, grudgingly click the "Empty Cart" button after reality had kicked in and I'd calculated the final cost!

East Indian Rosewood

I've never been one to horde wood, preferring instead to order materials to satisfy immediate needs, but after my recent purchases I must admit it's nice for a change to be able to pick and choose from the growing collection of soundboards and back and side woods awaiting my attention. I can see why wood acquisition can become an addiction for many builders!


Tuesday, November 16, 2010

Routing the Saddle Slot

None of my jigs are particularly attractive, polished or professional, but they're certainly functional and take the guesswork and inconsistency out of many tasks.

Routing a slot in the bridge blank into which the bone saddle will be fitted is one job I've given over to the ugly but effective jig pictured below.

The Macassar ebony bridge blank is affixed to the base of the jig using double-sided tape (what would I do without it?); the blank's positioning isn't really critical. The blank is bedded down with a few taps from a soft-faced hammer which more than adequately secures it for the duration of the process - the tape is tenacious stuff!

As you can see, two adjustable guides sit atop the jig and, with the plunge router riding snugly between them and the router bit sitting just proud of the wood surface, are adjusted so that the bit will accurately track the line of the saddle marked on the bridge blank.

I rout the slot in several passes, each one a little deeper than the last, until I hit the depth stop set on the router body.

I'm tempted to add sliding stops to either end of the jig to limit the router's travel, but for now, a couple of strategically positioned panel pins serve this purpose well enough, which perhaps explains why I haven't been in any great hurry to make that modification - I'd rather be building guitars than building jigs.

I'll show the next stage of the process in a future post.


Saturday, November 6, 2010

Eye Strain Reduced!

For making marks on dark woods such as rosewood and ebony, I use these white ballpoint pens which I discovered at an art supplies store. They're a vast improvement over the graphite pencils I made do with for so long.


Tuesday, November 2, 2010

The Flat-Top Guitar That Isn't

With some exceptions, steel-string acoustic guitars - often referred to as "flat-top" guitars - actually have arched or domed backs and soundboards, the advantage of which is arguably more structural than tonal. There are those who would argue that where soundboards are concerned there's little benefit in introducing an arch, but I think it's widely accepted that a domed top is better able to flex with variations in humidity thereby reducing the chance of cracks developing over time.

The mating surfaces of the various braces attached to the back and soundboard are curved in such a way that the dome is maintained in the finished instrument. Typically, the top assumes the shape of a section of a sphere having a 25 foot radius, while a 15 foot radius is commonly used for backs.

The following sequence of photos shows the method I use to shape the braces:

After the brace stock has been thicknessed to 7mm, I pencil the radius onto the brace blank using the appropriate acrylic template. In this case, I'm shaping the braces for the guitar back.

A 12-inch disk sander makes short work of the excess wood outside of the pencil line and it's surprising just how accurately the curve can be defined at this stage. A shop vacuum hooked up to the sander takes care of the wood dust pretty effectively.

With very little additional effort, the final arching of the brace can be established. Here, I'm using a hollow form whose radius matches that of the finished brace. Using 180-grit and 240-grit sandpaper in turn, the radius is accurately sanded into the brace. The scrap of wood held in place by my right hand helps prevent the brace from rocking sideways as it's sanded.

The finished back braces, ready for gluing.