Friday, April 27, 2012

Understand the Spindle! Part IV

I seem to have made a mistake in my calculations.

A rim weighted whorl does tend to slow the copp/ spindle system after the copp has gotten large enough to act as a good whorl.  This was my basis of analysis for suggesting that whorls be removable so that they do not slow the spindle as the copp is finished.

Center weighted whorls on the other hand, can be fixed because they do not tend to slow the spindle as much.

A drop spindle for travel

Rim weighted whorls do have their uses.  This compact spindle was make for producing 6,000 ypp singles while out and about.

 The shaft is rosewood, the hook is steel, and the whorl is a steel machine nut threaded on a piece of rose wood.  The shaft weight is 3 g, and the whorl weight is 15 g for a total weight of 18 grams

 An evening's spinning, just over a hundred yards -  not much because I had managed to get some epoxy under the skin of a finger and it hurt.

In contrast, here is my current production spindle for 9,000 ypp singles:

 The whorl weight is 15 g, and the shaft weight is 5 g for a total weight of 20 g.

 Yes, the production spindle is faster. The rim weighting of the compact spindle slows it down.  Despite being heavier, the center weighted spindle spins faster, and transfers twist to the yarn faster.

These spindles do not push the limits.  They could be used upside down as bottom whorl spindles.  9,000 ypp singles are plenty strong enough to withstand a half-hitch.  Problems with the strength of half-hitches do not show up until higher grists.

Where were such tools when I was learning to spin?  Nobody was talking about them and nobody was selling them.

Tuesday, April 24, 2012

High Whorl vs. Low Whorl Spindles

The choice between high whorl and low whorl drop spindles in usually presented as purely personal choice.  However, there are rational factors that should enter into the selection of a spindle for a particular project. Both styles of spindle have their virtues, and things that they do less well.  Between them is a middle ground where either will serve.

Bottom whorl spindles are inherently more stable.  They are suited for robust designs which tend to be heavier, and less fragile.  These designs have substantial mass (more than 30 grams) and are suited for plying and making singles with grist of less than 6,000 ypp.

Top whorl spindles can be made lighter, so that less effort is required to accelerate them to very high speed.  The high speed makes them suited to spinning high grist singles.

This is not to say that it is not possible to make a heavy top whorl spindle. However, if you want a heavy spindle, you might as well go for the stability of a bottom whorl spindle.

A heavy spindle will not spin high grist singles as fast as a (center weighted) light weight spindle. Thus, the bottom line is that a well designed top whorl spindle can spin fine singles (greater than 9,000 ypp) several times faster than a bottom whorl spindle. This is an advantage that no amount of skill or experience can overcome.

A heavy (rim weighted) spindle delivers torque to overcome the higher resistance of  low grist singles and plying. For these duties the heavier spindle is better, and gets the job done faster.  There is nothing as frustrating as trying to spin a low grist single with a spindle that does not carry enough momentum.   (Yes, Virginia, you need to ask Santa Clause for 2 spindles;  a light one and a heavier one.)

So the next time a spindle vendor tells you that their spindle is "fast", ask,  "Fast for what?"  A spindle that is fast for plying and low grist yarns will be slow when spinning lace singles.  A spindle that quickly spins lace singles will have problems spinning low grist singles (or plying).  If they say for spinning lace, ask them what they mean by "lace".  These days, lace can mean anything from 4,000 ypp to 30,000 ypp and that is a huge range.

No drop spindle is as fast as a properly selected, and tuned, DD flyer/bobbin assembly.  However, the correct spindle for the job is a whole lot faster than the wrong spindle for the project. 

Thursday, April 19, 2012

The sum of what I know about spindles

I have often said that I do not really understand spindles.  It turns out that part of  the problem was that I did not like modern spindle designs for the kind of singles that I was trying to spin.  The conventional wisdom of modern spindle design did not apply to what I was trying to do.

Here are spindle designs that work for me.  They are designed to spin 9,000 to 12,000 ypp singles at a good rate of speed.  The removable whorl allows continued high speed spinning even after the the copp gains enough mass to affect the rotation speed of the spindle - just take the whorl off and use the copp for rotational momentum.  The materials are rosewood  or ash shafts and ebony or cocobolo whorls.  The  whorls are in the shape of perforated truncated cones. These are more effort to fabricate than cylinders or disks, but are traditional, and do seem to work better. I use steel hooks and brass brads on the bottom.

For a short time, someone using a Peruvian folk spindle

might be able to keep up while spinning 10,000 ypp singles, but not for long - the physics are against it. For a spinner to try and spin 10,000 ypp singles on such a large whorl spindle means that they do not really understand the spindle. Certainly, it can be done, but it is a lot of effort.  With the correct spindle, it is much less effort. On the other, hand spinning the low grist yarns in the photo above using one of my spindles designed for fine spinning would be a huge effort.  It could be done, but it would be a huge effort.  A spinner that understands spindles, chooses the right spindle for the task.

Teachers that say, "A good spinner can spin anything on any spindle" either do not understand the physics of spindles or they do not care if their students waste time and effort by working with the wrong tools.

As the copp grows, the rotational speed of the spindle declines, and with a large copp, the additional weight of the fixed whorl limits the maximum rotational speed of the spindle. This is the reason for a removable whorl.  It makes spinning that last third of the copp much faster.

Let us consider a recreational spinner drafting 100 inches per minute. If spinning singles to make 2-ply worsted weight yarn, then the spinner needs ~400 or 500 rpm, (average) and 3 inch whorls work very well. If the spinner is spinning 6,000 ypp lace singles then they need ~ 900 rpm to get the twist to hold the yarn together, and for the same weight whorl, it should be ~1.5" in diameter. (However, likely it will be lighter.)  My whorls have an average diameter of ~1".  A  10,000 ypp single requires 3 times as much twist per inch as  a 1,600 ypp single.  Thus, for me to spin 100 inches per minute, I need to average more than 1,200 rpm to insert the twist to hold that fine single together.

Spindles store energy! Twist is energy! Twist energy is inserted into the yarn from rotational energy stored in the spindle. If a spindle keeps spinning for a long time then it is slowly transferring energy to the yarn, that is: it is spinning slowly!  A belief that a spindle can transfer energy to the yarn and keep rotating is a belief in perpetual motion.  A spindle that slows down and stops, is a spindle that is doing its job.

The spindle with the smaller diameter whorl is going to spin faster. It is going to transfer its energy faster. Then, it is going to slow down and stop - it has done its job.  It is a fast worker.

Tools matter!  Any tool that can be made, can be made better.

ETA 4/23 Lignum is better than ebony for whorls.

Sunday, April 08, 2012

Understand the Spindle! Part III

The next set of questions has to do with how the spindle is spun-up, and how much energy is in the "flick".

There are several "finger flick" motions that can be used to spin up a spindle.  These can give a spindle with a 2 inch whorl some 400 rpm.  That means they can give a spindle with a 1 inch whorl as much as 3,000 rpm depending on how the flick is delivered.  However, a smaller whorl diameter is likely to have a smaller diameter blade (the chopstick like stick in a spindle system).  A smaller diameter blade has a smaller circumfrance, which must rotate more times during the flick, so that a smaller diameter blade can produce much higher spindle speeds.  On the other hand, large whorls will need larger blade diameters to provide the torque to get  larger whorl rotating.  Thus, if you want to spin fine yarns fast, smaller whorls allow smaller diameter blades, which allow spinning the spindle faster during the flick.

In short, it is a system, and by changing the diameter of the whorl and the blade, we can make spinning one kind of yarn easier (and spinning another kind of yarn more difficult.)

The amount of energy that can be delievered to the spindle in one flick is limited.  As the weight of the copp grows, that weight and the weight of the spindle must be both be spun up.  Since some of the energy goes into accelerating the copp, there is less energy to accelerate the spindle.   Thus, as the size of the copp grows the spindle speed is reduced.  This effect can be reduced by using a removalbe  whorl.  Then the whorl is removed when the copp reaches a critical size and spinning continues using the copp as the "whorl".  This allow faster spinning and bigger copps to be built.

The total weight of the system is limited by the tensile strength of the yarn being spun. Fine, soft yarns can not suport as heavy a spindle system as a hard spun cord.  Wool cannot support as heavy a spindle system as linen, cotton, or hemp, and so forth.

On the other hand, spinning hard spun cords require heaver spindles and whorls with longer lever arms to insert twist into yarns with more spin rigidity.Thicker yarns require heavier spindles to hold the fibers in alignment as twist is inserted. (Even with woolen yarns, some parts of some fibers have to be held in alignment so that they can be wrapped around each othe to generate the friction to hold the yarn together.)

Thus, we can design or select a spindle to facilitate the kind of spinning that we want to do.

For strong/ heavy cords/heavy plying : A heavy spindle with a large diameter whorl such as a Navajo or dare I say it?  (I dare!) the old Ashford spindles.

For singles for 2-ply worsted yarn:  This is where the common modern designs excel with ~3" whorls and total spindle running weights ~2 oz.  Cupped or weghted whorl rims allow slow, carefull drafting for spinning very pretty yarns.

Lace singles (6,000 - 12,000 ypp) :  Here modern spindle designs get schizophrenic, with light weight but long lever arms.  I like a removeable whorl bead (sometimes a metal nut) with a total spindle weight near 0.7 oz. Whorl diameter varies from 0.5 to 1" depending on the desired yarn texture. As the copp grows, I take the whorl off and allow the copp to act as the whorl, so that the final weight of blade and copp of 560 yards is only a few grams heavier than the original blade and whorl weight.

Fine Singles (grist greater than 12,000 ypp): Supported spindles (Russian & Tahkli ) work very well, but drop spindles can be much faster.  The trick is to use thin blades and small whorl beads.  In particular, top spindles spun up with thigh rolls can allow rapid production of fine singles.

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  ( ).  These are spindle with wide, thin whorls that spin slowly for a long time.  The classic Russian supported spindle ( 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 , , , , and .  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 ( 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.

Wednesday, April 04, 2012

Understand the Spindle!

What could there be to understanding a simple spindle??? What could I say, that other spinning teachers have not already said?  This post is not about basic spinning with a spindle, it is about becoming a very good spindle spinner, quickly!

Spinning is about inserting twist into a fibers.  Twist is energy.  Inserting twist is physics. A full understanding of spinning includes understanding the physics of the situation well enough to understand why different kinds spindles are better for different kinds of projects.  Understaning the physics of spindles will help you choose more functional spindles and help you match the project to the spindle.  The right spindle for the project will help you spin faster.  The right spindle for the project will help you spin finer.  The right spindle for the project will help you avoid overspin!  (I am not kidding!)  The right spindle will help you spin thicker. 

Physics gives us a model so that we can understand what kind of spindles will work better for different kinds of yarns.  This means that we do not have to experience every kind of spindle before we can pick the right spindle to spin the knid of yarn that we wish to produce as the next project.  This makes learning to spin easier, faster, and cheaper.  That is, we do not have to have spun with (own) all kinds spindles to know what spindle is right for the yarn that we want to produce.  It takes much of the trial and error out of becoming a very good spindle spinner.

There are a lot different ways to "spin-up" your spindle.  Supported spindles want to be "spun-up" one way and top whorl drop spindles want to be spun-up in other ways.  Read "Amos" and  talk to your spinning teachers.  Learn all the ways that your spindles can be spun up.

For a particular spinner at a particular time, a specific spin-up technique will impart a certain amount of energy into the spindle. For now, I am going to call this a "flick", however the energy is delivered to the spindle. That energy will be expressed as rotation, or angular velocity. The speed of rotation will depend on the energy the spinner is able to deliever, the total mass of the spindle, and the distribution of the mass with respect to the axis of rotation.

If the spindle is light in weight (low mass) the spindle will spin faster.  If the spindle is heavier, the spindle will spin slower. A flick will cause a supported Russian spindle made from the the local (Russian) pine to spin faster than the replica turned from maple, because the pine spindle is lighter than the maple spindle of the same dimentions. On the otherhand, each spindle contains one flick of energy and will insert the same total number of  twists into a thread of the same fiber and grist.  However the pine spindle is rotating faster and thus will deliver its twist faster, so that the spinner will need to draft faster when using the lighter pine spindle.  The  maple spindle will spin slower so the spinner has more time to draft.  The faster drafter will have to wait for the slower maple spindle to deliver the twist required to hold the thread together.  Where the form factor is the same, the lighter spindle will spin faster (given the same flick).  However, the recreational spinner may (very likely) prefer the slower pace of the slightly heavier spindle.  Or, a "Russian" spindle turned from basswood, will spin faster than one made from Russian pine because the basswood spindle will be ligher than the pine spindle.

For two spindles of the same mass, the spindle with more of its mass farther from the axis of rotation will spin slower when given one flick of energy.  Again the total energy available to insert twist is the same in both spindles.  However, the spindle with its mass closer the its axis of rotation (e.g., Russian spindle) will spin faster than a spindle with (some of) its mass farther from its axis of rotation (e.g., a "CD spindle").  Thus, the Russian spindle is more suited to fine grists that require 30 tpi to hold together and the CD spindle is more suited to grists that will hold together with only 4 tpi.  Because the Russian spindle is spinning fast, it will deliver its energy and slow down rapidly.  Spinning at ~500 rpm the Russian spindle will deliver the twist for 16 inches of thread  (at 30 tpi) in about one minute and come to a rest.  In contrast, the CD spindle may only be spinning at 50 rpm so that it takes 10 minutes to deliver its energy.  Thus, it takes the CD spindle a very long time to twist a fine thread, so people do not use CD spindles for fine spinning, they use them for thicker yarns that require less twist to hold together.  These thicker yarns develop more twist rigidity and take more energy to twist, so that for the yarns that CD spindles are used to spin, CD spindles slow down and stop in much less than 10 minutes.   However, given the same kind of "flick" a CD spindle and a Russian spindle of the same total mass carry the same energy, but they rotate at different speeds.