Sunday, September 30, 2007

Unison Bridge... part 1



There are two bars that go across the soundboard that the strings are stretched over (one bar is called the bridge, the other is the nut).

In the pictures here you can see the beginning of the bridge. So far it's sawn out to rough size and shape... now I need to shape it to the exact dimensions with a spoke shave.

The plans for the instrument provide measurements for four cross sections of the bridge, down to the 1/100th of an inch. This is a critical part of the instrument because errors in the dimensions could cause the strings to buzz, and it also affects the scale quality.

(In the picture, everything is upside down, but you can get an idea for where things go.)

Thursday, September 20, 2007

American Woodworker

There's a good article about my project in this month's American Woodworker, in conjunction with a great story on the hobby shop!


Go grab a copy! :)

And thanks to the folks at American Woodworker!

Milling the Rose; Milling the Bridges

Almost all the remaining wood I need arrived from Hearne Hardwoods this week. I got some massive boards... e.g. a 24" wide piece of European beech that weighs over 100 lbs (in image). I also got a really nice piece of Gaboon ebony for the key veneer.

The beech for the bridges came 2" thick; the bridges are only 0.5" thick on average. I started milling down the planks to rough size today, cutting a chunk out of the big beech plank and flattening a face on the joiner.

Today I also milled down the rose from before. I reduced the thickness of it to less than 1/8" by sweeping the back of it with the mill. I also used an indexing head to clean up the punched pattern around the rim, and cut off the excess material.

Thursday, September 06, 2007

Soundboard, part III


Planing to thickness
The resawn boards were about 1/4 to 5/16 inch thick. They need to be 9/100ths of an inch thick. I was afraid to use the thickness planer to go less than 3/16ths of an inch thick; beyond that, it is all hand planing.

The piece show in the picture at right is to the correct thickness for now (1/10th of an inch). I have four more boards to plane, and then a small amount to remove with a sander.

Soundboard, part II


Joining
For the past four days, I've been gluing the boards together with hot ground hide glue. This glue, as the name implies, melts around 150 degrees F and gels within five minutes. It cures very hard and resonates with the wood. It is the same kind of glue that was used in the original instrument.

The Soundboard, alla New Yankee Workshop

Resawing
The boards from Switzerland came about twice the thickness I needed. My first step was resawing the wood (cutting it down its length) into half-thickness pieces. This was done on the bandsaw with a fresh blade and a point fence. (The piece of wood in the picture was a scrap that I tested the fence setup with.)