Why 10mm? The one I brought back from Oz is only about 6mm thick (34cm long x 8cm wide). I am under the impression that it's the wood that makes the noise not the string (I could be wrong) 'cos the frequency is independant of the string length (I need to test that a bit more though). To stop the string wearing I made sure the hole was very very smooth.
I think they would be great tools to call everyone to the fire at a camp instead of a whistle! But i don't do communal camps anymore
To be honest I used 10mm because that's the thickness the wood was
It tapers round the whole roarer though. The only reason I suggested one thicker was because the tut I saw which inspired me to make it was about a finger thick, and because I think it would work better if it was a bit heavier than mine, because it would have more momentum.
To be honest when I said:
From what I can tell, it works by the roarer spinning around (and thus winding up the string) as you swing it in circles, and when the string can't take any more tension it springs back, creating the sound.
I phrased it kinda badly - what I meant was that when the string can't take any more tension, it springs back and the roarer spinning rapidly in the other direction makes the noise
I think anyway, it is just a theory...
It would be quite a useful tool for calling, but you'd need one a bit louder than mine I reckon, I might make a slightly bigger and heavier one and retire this one to the wall
Cheers,
Pete