Saturday, November 16, 2013

Stone Whorls

My sister is a world class goldsmith.  Since he retired in 1980, my father has been doing lapidary work for my sister.  He does fine, one of  kind, gems for her small sculptures.

Fifteen yeas ago he bought a big lot of fine jade, and for the last couple of years we have talked about him making me some stone whorls from that jade. My sister has superb drawing skills and he is accustomed working from drawings. Along the way, I did a lot of calculations.   I made spindles that accepted interchangeable whorls, and tested various shapes of whorls.  I bought "whorl" beads of various kinds and tested them. At one point, I made a full set of  CAD files for the project.   And, I talked to folks like Stephenie that have collections of  real neolithic spindle whorls.

My conclusions were:

1. Stone spindle whorls are fragile and they tend to get lost. 

As a result, I expected production spinners to use the least expensive whorls available.  This is born out by the large number of crude stone and ceramic whorls that  have been found. My response was to use machine made whorl beads.  Today, a broad variety are available, and can easily be tested.

2.  "Carved" whorl beads tend not to be very well balanced so that substantial amounts of rotational energy goes into gyroscopic stabilization rather than into twist, and spindles with carved whorl beads tend to slow rapidly. The  goal of spinning is to insert twist quickly.   Energy going anywhere but to insert twist is BAD.

3,  Carved whorl beads tend to have more aerodynamic drag and hence tend to slow more rapidly.

4.  Production spinners, seeking to spin as fast as possible are very unlikely to use carved whorl beads  in their production spinning. Carved whorl beads are a store of value, rather than a functional tool for rapid yarn production.

5.  I preferred smaller, higher density whorls made of metal.  For example brass is ~ 2.5 times denser than jade. I quickly discovered that for fast (worsted) spinning, I liked small, well balanced brass whorls much better than even very well balanced jade whorls. And, the metal whorls were cheaper, and less fragile. In any industry, production workers who buy their own tools, like cheap and durable.  I made a lot of brass whorls to test.  I liked the way the worst of the brass whorls spun better than the way the best stone whorls spun.  I came to feel that better spindles and therefore cheaper textiles was one of the major contributions of the bronze age. I told my dad not to bother making those stone whorls for me.

The above was all done when I was mostly spinning and thinking about worsted 5-ply knitting yarn with singles running 5,600 ypp.

This summer, I have been thinking about woolen spun yarns for weaving.  Woolen is a different kind of drafting and it makes different demands on the spindle.  Why should I use the same spindle for woolen and for worsted spinning?  Why does a spindle used for woolen spinning need the large moment of inertia provided by a whorl?  

The way (with a hand spindle) to quickly spin a lot of woolen yarn  with a hand spindle is with a 'twisty stick'.  A whorl just slows things down.  Yes, you need a whorl for worsted spinning (wool or cotton).  Yes, you need a whorl for linen, hemp, and nettles.  Do your physics home work, and calculate the moment of inertia that you require for your current spinning project.  It may be smaller than you think.


Susan Stewart said...

The archeological evidence is limited, but in th eUK at least lead whorls, with some pottery, and wood and the occasional bone spindle are what show up.

Easy to use and easy to replace with no special skills required-you break a spindle and there's a nice pile of sticks or the remains of lunch from a few weeks ago from which you can easily whittle a replacement. Clay and lead whorls are easily made with none or little specialized technology-I've made lead weights for fishing myself melting down old lead pipe and low tech molds (my Dad was a bit of believer in Doing Thing Himself no matter what the safety issues!) and making lead whorls would be no more complex.

However brass or other metal spindles require more technological sophistication and hence would need to be traded and specialist manufacture. And would be more valuable. We find no such evidence of manufacture or trade or mention in wills.

Doesn't rule it out as a possibility of course, but just because something would have done the job better doesn't mean it was actually used.

Aaron said...

Lead is heavier than bronze, iron, copper, tin (or silver) and thereby a lead (or gold) whorl has a different design. Pewter was available after 1500 BC and would also work.

I was working my way up to higher specific gravity whorl materials, liked (brass) and stopped.

If folks are riding iron shod horses, the culture understands the smelting and forging of iron. Blacksmiths know how to make tools. If shipwrights and masons have steel tools, than spinners and weavers also have access to steel.