13th Century Sinphone (early Hurdy-Gurdy)

This has been a very interesting project.  I started without plans or technical drawings, with only an image of a woodcut and no real knowledge of the workings of a Hurdy-Gurdy.  I actually started cutting wood before I saw the first images of the workings of a Hurdy-Gurdy.  With the help of the Hurdy-Gurdy mailing list members, and Alden and Cali of Olympic Music in Washington, I have made it this far.  This is an experimental prototype, I am using it to test design elements for a much more aesthetically pleasing 'final version'.  I will try to document the unusual experiments here as I make them.

The first unusual element is a Corian wheel.  I wanted to see if I could build a functional wheel that would not go out of true or out of round, that would not be affected by weather or by humidity. 

The next element I am going to try on the box is a bridge and nut made out of Corian as well - should make yet another improvement in environmental stability.




With one key and tangent set




Another view











All keys installed








Another view
















Turning the brass collar for the Corian wheel









Recess drilled with a 1.5 inch forstner bit on a squared drill press














Perfect fit of collar into socket






Rough cut on scroll saw















4-56 screws and washers through back of wheel, into threaded holes in the collar





Wheel blank drilled through, using collar as a guild, then mounted on a piece of the axle steel and fitted into the lathe for truing.  Lots of very fine dust when working Corian













A propeller balancing tool for model aircraft is a perfect run-out tester.  Thin aluminum foil shims added behind the collar until 0 run-out achieved.






The old maple wheel out, the new Corian wheel in.  The strings have just been re-installed, and have not been re-cottoned.  The wheel needed 'primed' with rosin/alcohol mix before it held rosin well.










This is the new Corian nut set.  It is very smooth, very hard, and seems to do a great job.



This is the new Corian bridge set.  The HG responded better with a wooden bridge on the mouche, so I left it as hard maple.  The Petit Bourdon and chantrelle bridges work very well out of Corian - it is smooth and slick and doesn't even mark the strings, and doesn't need lubrication as long as you polish it well.  The wheel is a baltic burch ply wheel - I like it best of all the ones I have tried so far.