Friday, January 1, 2010

First Shawm - Tuning 2

Having played the gralla, I had a better feel for how the whole reed/staple/pirouette thing should work.  It was time to apply it to the homebuilt version. 

I used the gralla reed for initial testing, and made a pirouette to suit this.  The outer diameter of the pirouette was set by the diameter of the shawm's body, and the length was set by eye and guesswork.

I turned the first pirouette between centres, and didn't do much about turning the cup out. After cutting it off the lathe, I drilled the centreline by eye, reamed it to fit the shawm's staple, and opened out the inside of the pirouette with drills and countersink bits.

Looking at the gralla reed relative to the bagpipe chanter reed, it seemed that a shorter chunky reed was quite a good way to go.

Fellow choir member Lindsay generously donated a batch of pre-loved/run-in/used bassoon reeds from her stock, and I was in business.

The binding on the bassoon reeds is rather chubbier than on the gralla reed, so I had to enlarge the inside of the pirouette to allow for this, which was the work of a few minutes with the drill press and an 11mm drill .

Here's a close up of a reed and pirouette on the shawm.

The shawm, now with a full octave of finger holes, tuned with a bassoon reed.
The hole spacings are based on the limits of what my fingers can reach.

Close up views of the central finger holes. 
Older filled-in holes are also very visible.
The chamfering around each of the holes serves two purposes:

  • it helps fingers locate the holes and seal them properly and quickly,
  • it removes the tatty finish around the holes caused by drilling and filing them to size. 

The downside of using rimu for the instrument is that it is not a particularly fine grained wood, so a clean finish around holes requires some attention.

Placing these holes went quite quickly.  I did this octave set of holes in about two hours.  However, as holes are added further up the body, these affect the tuning and intonation of the lower holes, so I need to work back down the row making adjustments.  This will not be anywhere near so fast.

The to-do list now stands at:
  • adjust the tuning, especially the E and the A.
  • do a lot more Practice!
  • do some fine shaping of the inside of the pirouette, since the binding of the reed is still jamming, which affects the playing action.
  • consider refinishing the outer surface and varnishing it (quick and dirty with polyurethane, I'm afraid. The period finish will be on the next one).
  • sealing the inside of the bore (thinned down varnish on a pull-through cloth, or something similar).

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