Tuesday, April 14, 2015

Spinning at more than 210 wpi

I recently mentioned that 56 count wool spun at its spin count is a bundle of 20 fibers. Such a bundle  is just over 125 microns in diameter. The best parts of the Rambouillet fleece that I get from Anna Harvey are 80 count or ~18 microns in diameter, so a bundle of 20 of those fibers will be just over ~90 microns in diameter -- easily much less than 1/210 of an inch, so we can expect wraps per inch of 210 or more from a bundle of 20 fibers.

Drafting 20 fibers from 80 count wool is not that different from drafting 20 fibers from 56 count wool. Making yarn from those drafted fibers just takes some 22-24 tpi, fingers sensitive enough to control the flow of twist up into the drafting triangle, experience to know what the single you want looks like, and the courage to spin that fine.  Oh!, and very well prepared fiber that drafts easily.

The path to spinning 80s (210 wpi) is:

  1. Knowing it can be done.
  2. Wanting to do it.
  3. Having the tools.
  4. Building the skills.
Today the main problems are that most spinners do not know it can be done and the tools are not widely available.  However, any wood turner with the skill to make a functional wine barrel spigot has the turning skills to make the appropriate bobbin and whorls.  You can find somebody like that at any wood working club, and there are wood working clubs everywhere.   Alden Amos's Big Blue Book will give YOU a path to the calculations for the necessary whorl diameters.

ANYONE who says singles of 210 wpi cannot be spun is ignorant of both science and history.

I will say that double drive, with  differential rotation speed is far, far, and away the easiest way to spin 80s. Then, a spindle of ~15 grams - I use a drop spindle with a removable whorl so as the copp builds, I can take the whorl off and use the copp as the whorl.  Then, comes Scotch tension.  And this afternoon, I just cannot seem to be able to tweak my IT enough to spin 80s on a practical basis.

The steps from 10s at 75 wpi to 56s at 175 wpi are easier than the step from mediums at 175 wpi to fines at 210 wpi.  Thus, I suggest that anyone planning to spin 80s make up the whorls required for 10s, 20s, 40s, and 60s, and the build the skills required for spinning each of these threads in a step wise fashion.

=> I use flyers where the flyer whorls are threaded to fit onto the threaded end of flyer shaft.  Then I use threaded inserts in the center of the flyer whorl.  The threaded insert is placed in the whorl blank, and then the whorl is turned on a bolt screwed into the insert, and held in the jaws of the lathe. Required precision for turning flyer whorls for spinning 80s is about 1%, so a 50 mm whorl needs to be turned within 0.5 mm or 1/50" of the design dimension.  Lower count singles require much less precision in their whorls.

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