Thursday, April 05, 2012

Understand the Spindle! part 2

In Part I, I mentioned mass that is farther from the center of rotation slows the rotation of the spindle.  This is a dramatic effect.  Suppose you have a spindle with a 12 gram whorl in the shape of a flat disk. If that whorl is 1 inch in diameter, then the speed will be X for one "flick" that gives the spindle rotation.  If the spindle is made with a thinner whorl, then a 2 inch diameter whorl, still weighted at 12 grams, have a speed of X/8.  If the spindle is made still thinner so that it has to be 3 inches across to weight 12 grams, then the speed will be X/27.  That is, a spindle with a 1 inch whorl will spin 27 times faster than a spindle with a 3 inch whorl when they both carry the same rotation energy.  When spinning yarns of the same grist, the spindle with the 3" whorl will deliver its energy to the yarn much more slowly and be much more suited to spinning thicker yarns that require much less twist per inch.  The 3" whorl also has a longer lever arm and thus can deliver more torque.  Thicker yarn requires more torque to insert  twist into the yarn.  Thus, large whorls are better suited to spinning thicker yarns and small diameter wholes are better suited to spinning finner singles.

Cupped and rim weighted whorls, where even more of the weight of the whorl is farther from the axis of rotation result in even slower spindle rotation. This is not bad if you are learing to draft, but it is no good if you want to spin a lot of fine yarn, fast. The classic example is the CD spindle  (http://danielson.laurentian.ca/qualityoflife/Fulltext/Textiles/Making_a_cd_drop_spindle.htm ).  These are spindle with wide, thin whorls that spin slowly for a long time.  The classic Russian supported spindle (http://askthebellwether.blogspot.com/2007/08/how-do-you-spin-on-russian-spindle.html) has its whorl very thick and close to the axis of rotation.  As I look around, the Russian support spindle and the Tahkli are the most comon fast spindles around.  However, it was not always so. 

We find large numbers of small "whorl beads" at sites around the world. see http://www.philamuseum.org/collections/permanent/139611.html , http://www.metmuseum.org/collections/search-the-collections/140002024 , http://antiquegreeks.info/?s=Bead+Spindle&c=37906 , http://www.stringpage.com/viking/spindles.html , and  http://www.woolery.com/store/pc/Medieval-Spindles-c281.htm .  Were these really used for spinning or were they just decorative beads?  Using metal machine nuts of size and weight similar to those described on the Viking page, I have made spindles that spin fine threads fast. To modern spinners that are accustomed to spinning with modern spindles that spin slowly, these spindles with small whorl beads spin disconcertingly fast.  Unlike the supported Russian and Tahkli spindles that are spun up with a flick, these top and bottom whorl spindles that I have been making can be spun up with thigh rolls and 2-handed tosses to truely high speeds.  Speeds that spindles with mass on a longer leverarm cannot match.

Nobody using a modern Peruvian spindle such as (http://abbysyarns.com/2011/02/peruvian-spindles-my-spindles) can spin that fast, because their spindles are have evolved by tradition to spin slower, with more torque to spin the coarse singles being produced for local utilitarian consumption.  In fact, there are modern Peruvian spinners that use metal machine nuts as spindle whorls. These spinners do spin fine threads fast, they just have not gotten as much publicity.

I do not want a spindle that spins for a long time.  When spinning fine threads (e.g., 100 wpi and much finer) , I want a spindle that transfers its energy to the thread  -- very rapidly.  That means, the spindle is spinning fast.  When my spinlde is inserting twist rapidly, it is putting energy into the thread and that loss of that energy will slow the spindle down rapidly. Thinking that a spindle can insert twist and keep on spinning is like believing in perpetual motion machines. Spindles store energy, they do not create energy.  A spindle that spins for a long time means that it is not transfering its energy to the thread.  A spindle that spins for a long time means that it is spinning slowly, transfering its energy to the thread slowly, and it is inserting twist slowly.  I am not saying that this is bad. It is necessary for thick yarns and for spinners that are slow drafters.  I am saying that traditional spinners used spindles that made spinning the kind of yarn that they wanted to spin easier and faster.  However, today we have a lot of spindles for spinning all kinds of yarns thrown on to the market, and they are not labeled as to what kind of yarn they were designed to spin.  Moreover, modern spinning teachers do not explain in any kind of  detail WHY such and such a spindle is better for a particular project.

2 comments:

tintinnael said...

Thanks for these fantastic posts! After I reached a certain point in my spinning, I started to get frustrated about the lack of "advanced" information available-- other than lists of exotic spindles and recommendations to buy a spinning wheel. I'm all for gadgets, but that's not very helpful when you're trying to focus on mastering the spindle.

I’ve noticed that ideas about spinning tend to be repeated without explanations of why they're true (or not). At least, it’s rare to see a serious attempt to figure out the mechanics. Now I'm starting to understand why I find spinning easier on my simple center-weighted bottom whorl than on some of my more elaborate rim-weighted spindles. (And I’d wondered why medieval Europeans used those tiny whorls.)

Spindles said...

Great post! Been reading a lot about spindle techniques. Thanks for the info here!