Saturday, July 05, 2014

50 mm whorls

The new whorls are about dialed in. I am pleased that they allow sustained bobbin speeds in the range of 3,400 rpm.  That is not peak bobbin speed, but is sustained bobbin speed. When spinning 5,600 ypp worsted (10s), that is 10 yards per minute.  Suddenly, turning out a knot free hank of 560 yards in less than 90 minutes is not a problem.  The intended weight of such hanks is 45 grams, and mine are running between 40 and 50 grams.  I think pretty good for hand spinning.  Spinning 20s (22 grams) goes at about the same rate or even a little faster.

My critics look at my pix, and say that I spin "thick and thin".  Perhaps!, but the average comes out to the grist that I want.  Can they sit down and spin their "uniform" singles, to produce 560 yards of the grist that they intend in 90 minutes?

With DRS, and these speeds, the spinning process is different.  There are videos of the way that I spin on this blog.  The top is wound onto the distaff, and is pulled off with my right hand.  DRS controlled takeup pulls the yarn out of the tip of the drafting triangle, while  my left hand controls how much twist runs into the drafting triangle.  The fibers in the top are parallel, and remain parallel in the drafting triangle, so that the final thread is full worsted. In other modern worsted drafting techniques, the fibers have a tendency to become skewed in the drafting triangle, and thus they must be pulled out straight and parallel again. This skewing of the fibers is inherent in the tension required to oppose the continuous take-up from a flyer/bobbin assembly not controlled by DRS.  I do not have  to resist that continuous take-up so I do not bunch up the fibers and push them out of their parallel alignment. My right hand controls attenuation, and my left hand controls twist, I do not draft per se.  This is not a process that works with Scotch Tension, Irish/German Tension, or double drive where DRS is not strictly controlled. It works better with finer singles. This is the fast and easy way to hand spin fine worsted singles.  And, If I have the drive band in the correct groove in my whorl, I know that the resulting hank will be close to the intended grist.

A video of the process shows me sitting there, making tiny hand motions.  It looks like I am treadling and nothing is happening.  The flier is moving much too fast to be captured on video. And, the video does not capture the thread being formed and wound.  At higher grists, the thread just disappears, so it looks like I am just sitting there treadling with no evidence that thread is being formed.

Yesterday, I did make a whorl for shirting/hosiery singles (soft and firm twist 40s, 22,400 ypp).  In a world where much of the wool was 40 count, it may very well be, that for spinners, it was faster to let the fiber flow through their fingers as above, to produce 40s, than to put extra effort into drafting thicker singles.  That is, the spinners traded more treadling effort for less drafting effort. And, the weavers gladly accepted the finer plies because it gave the fabrics a much nicer drape and hand.

Wood blanks to make whorls for "fines" are stacked  on the work bench beside the lathe. These will be for the #0 flier, but I have not designed that bobbin yet.  And, there is a real chance that fines will need a higher ratio accelerator.

A good production rate for shirting using these tools/techniques is 5 or 6 yards per minute, and the drafting technique works better at rates above 3 yards per minute.  This makes it seem like 240 yards per hour (bobbin =3,000 rpm) was a good commercial rate for a hand spinner.  Thus, a spinner could likely produce 4 worsted hanks per day.  Woolen spun requires more twist for the same grist, and thus with a wheel, my woolen yarn production at this grist is close to 200 yph.  For spinning fines, I have pushed bobbin speed as high as 5,000 rpm, allowing fines (more than 30,000  ypp) to be produced at 5 or 6 yards per minute.  This is fairly high effort and noisy, and I am not sure whether this could be a commercial rate.  

This rate of production can be easily sustained without ball bearings.  A wheel running at 3,000 rpm using leathers, bronze against steel and wood against metal bearings can sustain such speed when lubricated with lard oil. It is noisy, but all those bearing surfaces seem to last for at least 4,000 hours of use.

All in all, I think that professional spinners with flyer/bobbin wheels could have spun between 200 and 400  yards per hour of singles in the range of  5,600 ypp -10,200 ypp and between 200 and 250 yph  for grists in the range of  22,400 ypp (e.g., shirting and hosiery) .

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