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Monthly Archives: March 2012

Satinwood guitar

Although many people prefer guitars made of dark coloured wood, lighter colours can make good looking instruments too. The back and ribs of this one are in satinwood (Chloroxylon swietenia), a dense hardwood from Sri Lanka rarely available nowadays but which in Georgian times was widely used as a veneer in furniture making. It’s hard, brittle and difficult to work with hand tools but it bends fairly easily and, because it doesn’t contain large pores, finishes well with French polish. As its name suggests, satinwood is strongly reflective and when polished takes on a shimmering, almost iridescent, quality (sometimes called chatoyance) that’s impossible to capture in a photograph.

The rosette and bridge decoration are burr ash and the bindings are Rio rosewood. The soundboard is European spruce.

As usual, click on the thumbnails for a larger view.

Another impossible object

My son, who is an engineer working on the design of big diesel engines, tells me that it’s all too easy, especially with CAD software, to draw what seems a brilliant plan – only to meet derision when someone realises that it can’t be manufactured. You can imagine the sort of thing he means: a nut where there isn’t enough space to get a spanner in to tighten it; or the need for a long bolt in a place with insufficient clearance to get it into the hole.

As someone who works with wood, I enjoy teasing him with the complete opposite: something that self-evidently has been manufactured but that looks impossible. One example is the captive screw here. But that’s a bit of a cheat because it depends on exploiting the remarkable elastic properties of some woods when treated with heat and moisture. Better are the apparently impossible double and triple dovetails that I wrote about a year or so ago.

Here’s something in the same vein that can be sculpted out of wood with nothing more than a sharp chisel. Or, should you have one handy, a 5-axis CNC milling machine will do the job almost as well – see here.

For larger images, click on the thumbnails.