The Pulley Cometh

Yay!  So AVL did have a replacement after all for the distressed wooden pulley on my 16-shaft AVL.


They make it from plastic now.  Hopefull it'll be here soon!  I'm going to keep the wooden one, in case I ever want to have another replacement turned out of wood.


I was looking at the diameter of the bore on the worn-out wooden one.  It'll be interesting to see how large the bore is on the plastic one, as the original bore on the wooden one just really isn't visible anymore.  The increasing cone-shape of the worn bore...when I look closely, I see that there is coning happening on the front side of the old wooden one, too, and they kind of meet in the middle; thus it's probably not really possible to know the exact original bore in relation to the size of the metal rod that functions as an axle. 


Also: to cut down on the movement of the pulley along the axle, I'm going to constrain the pulley with twist-ties.  I don't think all that play is necessary, and I don't think it'll be too rigid.  I wonder if originally this loom had some sort of constraining rings on the axles.


The long life of the old wooden pulley, now to be retired, is a testament of the quality of the materials used to build these looms.  I think that it's taken a very long time to develop the conical distortion of the original cylindrical bore, but once it started getting cone-shaped, it kind of accelerates the bore getting even more cone-shaped.  I've noticed that there was a direct correlation of how much wood powder I was finding on the floor below the pulley and how much the cone-shape was increasing.  As in: the more cone-shaped it gets, the more wood is removed via the ordinary motion of the shaft-lifting cable just doing its thing; the more wood is removed, the more cone-shaped it becomes, and the more cone-shaped it becomes, the more wood is removed.  So there's sort of a scary geometric progression.  Better minds than mine could explain it precisely, but let's just frame this by saying that it was really time to get the new pulley. 


I checked the other wooden pulley (again, original to this loom), the pulley in relay to the treadle that advances the dobby, and it is *not* developing a cone-shape in its cylindrical bore.  Pretty sure that it's because the amount of stress on that pulley is vastly less than the stress placed on the one that relays to the shaft lift.