Carlos and I went to Westlake Plaza this morning, and while there we ducked into Home Depot to get some coated wire cable, crimps, and a 'swaging' tool, that is to say, a crimper. Not nearly as expensive as I'd thought it would all cost, so that was good.
We came home and after lunch I went downstairs to the garage and had a go at attaching the cables to the treadles. It was tough getting my ample frame inside the loom to sit in back of the harnesses, in front of the warp beams, but I did it! I had pre-emptively thrown the sheepskin down there in order to not have to sit on the cold cement floor. It worked nicely. Only when I was comfortably seated on the sheepskin did it finally occur to me that because this is an AVL, it would have been totally easy to remove the warp beams and the back beam roller, to permit access to the back and down into the area with the treadle pulleys!
Crimping the cables worked nicely too, and I got the treadles working just fine. It took a little figuring out, but I found that if I pushed the dobby-advancing treadle (the longer one, to the left) all the way down to the spot where it pulled the dobby to the next slot, and then attached the cable that causes the harnesses to lift to the right-hand treadle (the slightly shorter one) in its highest position, it worked. Then I tightened the turnbuckle on the cable that advances the dobby, for fine-tuning. I might have to tighten it a little more tomorrow or at some point - while wire cable is pretty inelastic, I would suppose that there will be - however small - some stretch.
Now I can 'feel' the way the whole mechanism fits together, in my mind, schematically, in a kind of three-dimensional moving diagram. Performing the reassembly of the mechanical dobby and then hanging the harnesses and tying up the treadles have all helped me build this moving diagram in my mind. Now I can easily visualize the entire concept and mechanism, all its parts moving together in simultaneous concert, from the dobby fingers and dobby bar to the threads being lifted (or not) in the harnesses, and the marvelous clacking motion of the dobby wheel going round. It's so beautiful. It's like seeing one of Leonardo da Vinci's splendid drawings of cogged machinery and clockwork come to life.
Beautifully simple, and so finely-tuned. The engineering of the AVL looms is legendary.
After that, I put a short 16-bar dobby chain onto the rotating cylinder of the dobby, and joined it with two wire ties. I had put one dobby pin onto each bar, so that each of the sixteen harnesses would be singly lifted in succession, to test everything. 16 harnesses adds an astonishingly large number of shaft lift possibilities; 8 shafts give a possibility of 256 different lifts; 12 shafts make 4094 possible lifts, and 16 shafts multiplies it to an astounding 65,534 possible sheds.
It took a slight shifting of the position of the cylinder in the dobby - I had to adjust its tension screws until it backed off very slightly from the dobby finger strike plates, just about 1 millimetre back, and then it worked very smoothly. I sat down and treadled through the sequence and each harness lifted in succession cleanly, the dobby wheel clicking merrily as I treadled.
One more micro-adjustment on the turnbuckle on the dobby cable - and the treadling was made slightly crisper and more 'snug'.
Then I called Carlos downstairs to show him the loom working. Yay!
The spring on the sprung wheel-bar that limits the advancement of the dobby cylinder is very resonant! I might see if I can muffle it a little bit with a bit of felt stuffed inside. I can certainly deal with it if it doesn't work, but I'll try.
Next: warping the first project on the AVL!
No comments:
Post a Comment