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

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!

How This Weaver Learned to Tell S & Z: End-delivery Shuttle Post #3

Introduction:
For years, I resisted identifying yarns by whether they were S or Z twist. “How could you possibly know whether you’re holding the yarn right-or-wrong-side up, I said to myself. (And I’ve heard others say it, too.) Often, I learn things when I have to teach something and this time it was for collapse weaving with overtwisted yarns. My toilet paper demo was a big help. I can’t remember how I thought it up.

What is S & Z?
Yarns have two directions of twist: S and Z. To see the direction of twist of a yarn, look for diagonal lines.

How to tell the direction.
Hold a length of the yarn taut. Look at it closely. You’ll see that the surface of the yarn spirals (note the diagonal lines). If the diagonal slants the same way as the line forming the middle of the letter S, then we say it has S twist. If it slants the same way as the line forming the middle of the letter Z, then we say it has Z twist.  That is why the twists are named as they are. The seine twine in the photo shows S twist.

You can see how the diagonal lines are formed when you look at the toilet paper demonstration again. Which one shows S twist? Which one is the Z? Read on.

What to look for.
Look for the bars in the two letters: S & Z. See that the bar in the S goes on a diagonal like the back slash on the computer keyboard: \. Also see that the bar in the letter Z goes in the same direction as the forward slash: /.

Does it matter if the yarn is upside down?
Here is a gorgeous black cord I brought back from Bhutan (I think). Note where the tassel is in the photo. I see that the diagonal lines are going in the Z direction here. What will happen when I turn it upside down? See the next photo.

Now the tassel shows that I’ve turned the cord upside down, so-to-speak. It’s still Z twist! No change in direction! No matter which way you turn a yarn or look at it, the twist will always look the same!!

Here’s a quick way to check S & Z that always works. (The way I do it.)
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! So, if the yarn in question has the same diagonal as you do when you swing your right hand, it’s an S-twist yarn. Swinging your left hand across your body gives you the diagonal for Z twisted yarns. 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 hand for the Z direction.

End-Delivery Shuttles: Part Two


Why use end-delivery shuttles?
First, speed: the weft yarn never tangles or jerks, so you can throw the shuttle as hard and as fast as you want, and you don’t have to stop weaving to unsnarl a backlashed bobbin.
Second, the selvedges: they are even, not loopy and not indented from wefts being jerked or snagged.
They are more complicated to make, so they are more expensive than boat shuttles, but can be well worth the investment. Short ones are needed for narrow warps and longer ones for wider ones. (The warp width should be more than the length of the shuttle).

What makes them work?
First of all, only the weft thread moves—not the pirn (That’s important because it’s the momentum of the revolving bobbin in a boat shuttle that created problems.)
Second, end-delivery shuttles have a tensioning device that regulates the tension on the thread, so the weft can snug itself up to the selvedge thread perfectly on each shot. The weaver never has to touch the selvedges.

What kinds of yarns don’t work?
Wefts that are flat strips such as ribbon or metallics do not work in end-delivery shuttles because the yarn twist as it comes off the pirns. A boat shuttle must be used or the ribbon will twist and twist. (Just like toilet paper if taken off on an end.) Monofilament also will kink (over twist).
Also, really thick wefts, such as rags and heavy rug yarns, can’t pass through the tensioning device.

As the yarn is unwound from an end-delivery pirn, its twist is changed by a small amount, usually about 1/5th of a turn per inch of yarn because the yarn comes off the end of the pirn. With most yarns the extra twist is not noticeable. This twist change occurs when yarn is taken off the end of any yarn package, even cones. However, cones are wound with the intention of being unwound off the top so there usually is no problem. (The toilet paper demonstration again.) See below to know if there is too much twist.

I always like to take yarns off the ends of spools and cones because they can be taken off fast. Taking the yarn off the side must be done slowly or the yarn will overspin and tangle on the spindle holding the spool. Here is the stand I use to hold my spools and cones when warping or winding bobbins or pirns. It’s important that the thread guides for the spool must be exactly over the center if the dowels that hold the spools or cones. It is meant to be used to double up weft threads when you want to weave with more than one thread together as a single weft. With this doubling technique, the multiple threads will stay together and not separate with some making loops while others remain straight as you weave along. More information and how you can make a similar arrangement at home is in my book, Weaving & Drafting Your Own Cloth on page 67.

How can you tell if a yarn twists too much? 
You’ll know if you’re adding too much twist if the weft kinks on itself. Conversely, if your weft becomes untwisted and pulls apart, you’ve taken out too much twist. If the yarn is somewhat overtwisted to begin with, adding even that much twist can make it more difficult to handle because of the kinks. You can always add or remove twist by turning the spool or pirn end for end. More on this coming soon.