S & Z Twist

Use Twist! Turning a Ball or Spool upside Down Can Effect the Twist of a Yarn! 

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Introduction: 
The diagonal lines you see on a yarn indicate the twist put into the yarn when it was made. We use the term S and Z to indicate the twist of yarns. Some people use the term clockwise and counter clockwise and even others say right-hand or left-hand twist.  See below for a quick way that always works to tell if the twist is “S or Z.” (Even if you turn the yarn upside down!) 

The twist naturally in yarns can be affected when the yarn is taken off the end of any spool, cone, pirn, or bobbin. When yarn is taken off the side, the twist is unchanged. It’s easy to see diagonal lines in toilet paper showing twist being added or not at all. If I turn  a roll of toilet tissue upside down, we can still see twist, but it will be in the opposite direction. Often times this doesn’t matter, but some yarns will kink up if more twist is added or come apart if twist is taken away. The photo shows how to avoid changing the twist direction by pulling the paper off the side of the roll.

An easy way to always  tell S&Z  
Knowing that most yarns are twisted in the S direction, and that the right hand is the dominant hand for most people, swing your right hand across your body. Start the swing with your hand at your side and swing it towards your left shoulder. That is the same diagonal of S twisted yarn! And swinging your left hand across your body gives the diagonal for Z twisted yarn. When I’m in a yarn shop I don’t actually swing my arm—I just swing my hand across my chest—right for S direction and left for the Z direction.

You can add S or Z twist when you unwind yarn from the end of a spool. When the yarn, as seen from the end of the spool, moves in  a clockwise direction as it unwinds from the spool, S twist is added. By turning the spool end-for-end, the yarn will move in a counterclockwise direction as it unwinds, adding Z twist to it (subtracting twist). S on Z would subtract, too, and Z on Z would add, etc. 

Tightening the twist would make the yarn slightly harder, and loosening the twist would make it slightly looser and softer.  

Basically, yarn comes off faster and without jerks if it comes off the top of  a cone, or end of a spool. Be sure you take the yarn straight up from the center of the spool or cone.

A vertical set-up can be as simple as a reed supported by two chairs. I used to say I’d never buy spools because they topple over. Now I know why: if the thread isn’t guided directly over the center of the spool the yarn won’t come off freely.

When yarn comes out of a ball vertically, as it does when it comes out of the top of the ball, it has added a twist just as though it were coming off the end of a spool. Turn the ball over to reverse the twist direction. 
If  you unwind the ball starting at the outside of the ball the amount of twist being added (or subtracted) increases as the circumference of the package gets smaller and smaller. However, if you begin to unwind a ball from the center of the ball where the circumference is small, you’ll be putting in the most twist at the beginning. That is because one twist is added for each time the yarn traverses the circumference of the ball. In other words, there are more twists per inch where the circumference is small.

If you take the yarn off the side of the ball, the twist won’t be changed.

By putting a cone on a lazy Susan, you can take yarn off from the side of a cone.

Use your S & Z Identifier Tool to Add or Subtract Twist to Yarns

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Introduction:
My previous post on July 8, 2020, explained how to identify S & Z twist easily. This post tells why it helped me reduce warp breakage. More S & Z information relating to bobbins, pirns, and weaving is in my book, Weaving & Drafting Your Own Cloth.

I was making a warp using a singles linen, probably 14/1, that I had in my stash. It kept breaking when it went around the end pegs. Actually, I could see that the thread was pulling apart. I figured that the way the spool was standing up on my spool holder was the problem: I was untwisting the yarn so it became enormously weaker. (Truth be told that was ½ of the breaking problem: the yarn was old.)

Notice the diagonal lines in the yarn and the toilet paper. They are all going in the same direction. That direction is called Z because it is the same direction as the diagonal part of the letter Z. I assume my warp thread was probably a Z twist singles.

I had my spool of yarn on the spool holder this way which was untwisting my yarn and causing it to break. It was set so the yarn was UNTWISTING as it came off the spool. This diagram shows the twist of the yarn in the opposite direction: we say S. That is because the diagonal lines are the same diagonal as the diagonal in the letter S.

I turned my spool end-for-end so then twist was ADDED which made the yarn stronger instead of weaker and the breakage stopped. (However, it didn’t make it strong enough to overcome the old age and the yarns broke instantly when I began to beam the warp! It all had to be thrown out!!)

At times you do not want to add or subtract any twist. Then you take the yarn off a spool on its side!

You can add S or Z twist when you unwind yarn from the end of a spool. When the yarn, as seen from the end of the spool moves in a counter-clockwise direction as it unwinds from the spool, Z twist is added. By turning the spool end-for-end, the yarn will move in a clockwise direction as it unwinds, adding S twist to it. (This option is not available with cones which are made to stand only one way up.) To understand S & Z twist read more in my chapter on shuttles in my book mentioned in the introduction.

Repeating the principle: which end of a spool the yarn come off from dictates the direction of the twist put into the yarn—because the yarn is coming off the end. Take the yarn off a spool on its side and no twist will be added or subtracted.

You can add or subtract twist not only by how you wind a pirn, but also by which end of the spool of yarn you take the yarn off. For consistent cloth you want the wefts to be totally consistent as to twist. However, a novelty cloth can be woven using different twists: depending on how you put a pirn on the winder or stand up a spool of yarn.

How to Add or Subtract Twist from a Yarn: Look at the Top of the Spool End Delivery Post #4

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Introduction:
Almost every yarn has twist (among the few that don’t are flat yarns like ribbon, reed, and metallics). Twist is what makes natural fibers hold together as yarn. It’s what makes the plies of thread hug together in a strong yarn. Even man-made fibers benefit from the twist. This post talks about slightly adding or subtracting twist by which end of a spool you take the yarn off of. These situations aren’t common, but may occur with over-twisted, unbalanced, or single ply yarns.

Three major truths about twist to keep in mind:
1. In general, adding twist makes a harder, stronger yarn.
2. In general, subtracting twist makes a softer, more easily abraded yarn.
3. Twist has two directions: S twist and Z twist.

You can add S or Z twist when you unwind yarn from the end of a spool.
When the yarn, as seen from the end of the spool, moves in a counter-clockwise direction as it unwinds from the spool, S twist is added.


By turning the spool end-for-end, the yarn will move in a clockwise direction as it unwinds, adding Z twist to it.

Repeating the principle: which end of the yarn package the yarn comes off from dictates the direction of the twist put into the yarn—because the yarn is coming off the end.

You can add or subtract twist not only by how you wind a pirn, but also by which end of the spool of yarn you take the yarn off of. Now, every time you wind or unwind yarn, you can slightly add twist, subtract it, or have no effect on it.

How you unwind a ball of yarn determines the amount of twist as well as the direction of twist. If the ball rolls around and the yarn comes off the side, you know that no twist is being added.


If the yarn comes out from the center and off the top of a ball a small amount of twist is added or subtracted depending upon which end of the ball is on top as usual.

If you unwind the ball starting at the outside of the ball, the amount of twist being added (or subtracted) increases as the circumference of the ball gets smaller and smaller. However, if you begin to unwind a ball from the center of the ball where the circumference is small, you’ll be putting in the most twist at the beginning. It will gradually get less and less as the circumference of the inside of the ball gets bigger as it is unwound, because one twist is added for each time the yarn traverses the circumference of the ball, making more twists per inch where the circumference is small—in the center.  If this is a problem (kinks in the yarn) let the balls roll around on the floor as you wind. Then any twist will work itself out before it gets to the winder


You can always check yourself with a roll of toilet paper so you don’t need to worry if you forget all of this!