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Farmer John

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Reply with quote  #1 
This is from the front cover of a Juki sm.  Little known and seldom mentioned, the proper twist of the thread is required.  I researched this when I tried to use a large spool of thread and had breakage every 6 inches.  Yes, the spool was S-twist.  Normally you won't run into S-twist thread, but, never say never.
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pgf

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Reply with quote  #2 
It seems like you'd have to go out of your way to make a machine so sensitive to thread twist.  Do you understand what causes the breakage with S-twist?
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Farmer John

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Quite the contrary, as a home sewing machine will just not sew with an "S" twist thread in the needle.  Why the "Z" twist thread works and the "S" twist thread unravels, I don't know.  Rest assured that all of the thread in your local store has a "Z" twist.  However, I was gifted an 8oz spool of nice red thread, which  caused my problems, and led to research on thread twist.  The spool of red thread was determined to be an "S" twist.  Apparently either twist can be used as a bobbin thread, but I haven't tried it out.  Here is information from Superior Thread...

----------------------------------------------------------------------

All threads which have the intended use of going through a sewing machine (whether you are embroidering, quilting, serging, or sewing) have a final Z twist. A Z twist allows the thread to go through a machine and stay together (not untwist as the thread passes through the machine). Whether the sewing thread is made in Europe, USA, Asia, or Antarctica if the thread is meant to go through your machine, it has a Z twist.

An S twist thread has an opposite twist and these threads are made for hand stitching and for specialty two-headed sewing machines which are used almost exclusively in construction of clothing and commercial textiles.

You may have also read about left hand and right hand twist. These terms are incorrect as well. S twist and Z twist are the terms we use in the industry and the relevance of the twist direction is not an important factor to consider when choosing thread for quilting or sewing, as all threads created for these applications will have a final Z twist.
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I assume that my spool of red thread was intended for the left hand head of a two headed industrial machine.  Knowledge is better than no knowledge, so it is better to know about thread twist if one encounters a sm that will not sew, as it could be the thread twist.
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laurainalameda

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Reply with quote  #4 
Folks who spin yarn have likely run into the S and Z twist before. Some crocheters like Z twist more than S. Z twist thread, I've noticed, turns up in old cones, usually bought in boxes or given to you , especially in areas where commercial sewing was common.

The bottom line is, some antique or vintage machines are picky about their thread. The older the machine. The nicer the thread they like. My transverse shuttle machines absolutely purr when I use Aurifil, an Italin made thread that is on the fine side, lintless, and up to their standard. A lady likes to be appreciated. I have a 15 clone I swear would sew well with thread I unraveled from the selvedge. She's a survivor. She dont care. So, after I have COA, prayed, shown the machin The Big Mallet, and had a diet Coke, I try giving it better and better thread. Usually, that is the key. When I hit the lotto, I will sew everything with Aurofil, but until then, I keep it for my best ladies and garment sewing.
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pgf

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Reply with quote  #5 
Quote:
Originally Posted by Farmer John
Quite the contrary, as a home sewing machine will just not sew with an "S" twist thread in the needle. Why the "Z" twist thread works and the "S" twist thread unravels, I don't know.


Interesting. I find that very strange, since I can't picture any place in the typical threading path that would impart or depend on a particular twist. (Assuming one is dispensing a side wound spool from the side, of course.)

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Farmer John

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Reply with quote  #6 
I agree with you, as I don't understand it either.  Could it be that on a round bobbin sm, the hook is always turning the thread in a circle, and you would want the thread twist to tighten, not loosen.  This means that I must try the "S" twist in a VS sm. Would you like me to wind some red "S" twist on a spool and send it to you for trial ?
I will put the red cone on the next white elephant  gift exchange, ha, ha.
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pgf

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Reply with quote  #7 
I also wonder if it affects oscillating hook machines, or only rotary. (Sounds like a mean gift for the exchange!)
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Bags

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Reply with quote  #8 
Quote:
Folks who spin yarn have likely run into the S and Z twist before. Some crocheters like Z twist more than S.


laurainalameda, that's the first thing that I thought of.  When I was first learning how to spin yarn, one of the first things we were taught was the S and Z twist.

Of course then you get into the "are you using it as a single or a plied yarn?"  Also, some of the knitters that came into the shop, would have trouble with different yarns because as they were "throwing" their yarn around their knitting needle, it would untwist the yarn.  And other knitters who "threw" their yarn with the opposite hand would sometimes over-twist the same yarn.

Never thought about it regarding sewing, but that makes sense to me depending on how the thread is coming off the bobbin.

Carol

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Phyllis1115

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Reply with quote  #9 
I had to think about this topic. Back in my dark ages, the mid 1960s, I absolutely loved the three textiles classes I took at Iowa State University. At the time, ISU was one of the top Home Economics Departments in the US. Most of the students detested the class. I remember the instructor talking aboiut Z and S twist, but cannot remember much or what she said. I am positive she did not mention machine embroidery.[confused] 

I've been told that during normal stitching, the thread passes through the needle at least 40 times. During manual machine embroidery using longer stitches, the tread passes through the needle far fewer times.

When sewing seams, we want to use a thread that remains tightly twisted. However, when doing manual machine embroidery, we want a thread that blooms a bit for fabric coverage. Manual machine embroidery using a knee lever to change stitch width, normally does not utilize lots of very short stitches in a row. When it does, the embroider usually does not include stitching 6 inches in a row. 

I do have a modern embroidery machine, but do not enjoy the process. Learning to use this sewing machine after losing my father and a couple months later, a much loved, very special cat, distracted me from a pit of depression. Modern machine embroidery utilizes many short/small stitches and requires a strong thread. Generally this thread is a polyester not cotton.

When creating embroidery such as vintage western wear using a vintage or antique sewing machine, the operator moves the fabric and the stitch width knee lever to make the design. The operator's talent blows my mind. I cannot do both the hand and foot exercise movements. I can move my arms or I can move my legs, but not both. [frown]

John, I'd like to test a small spool of your S twist thread. Most of my antique and vintage machines tolerate and even prefer fuzzy, thicker 40 or 30 weight not so high quality thread to highly finished 50 weight modern thread. These sewing machines were engineered to use the then available thread.



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Farmer John

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Reply with quote  #10 
Hi Phyllis,  PM me your shipping info, and I will get thread right off to you.
John
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Farmer John

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Reply with quote  #11 
pgf,  so far, I tried this thread only in a 31-15,, which is a oscillating hook, type 15 bobbin machine.  Lets see what Phyllis has to say when she receives some "S" twist thread from me.
John
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kndpakes

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Reply with quote  #12 
I am working on an Elna Supermatic at the moment and after reading this remembered seeing a blurb about using left twist thread for darning. Perhaps manuals are the source of incorrect terminology.

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Phyllis1115

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Reply with quote  #13 
Good illustration.
When darning socks by hand or with a sewing machine, we generally want good  coverage with a minimum amount of thread. The S twist will bloom slightly giving better coverage than the Z twist. Using a large amount of thread when darning socks, causes "bumps" and triggers blisters.
My mom, an excellent and thrifty seamstress and quiter, enjoyed mending and would not approve that I no longer darn socks. 

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kndpakes

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Reply with quote  #14 
I don't know if this is where S and Z come from, but I am going to remember it as the center slant of the letter matches the direction of the slant in the thread as shown in the Elna manual.
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pgf

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Reply with quote  #15 
Quote:
Originally Posted by kndpakes
I don't know if this is where S and Z come from, but I am going to remember it as the center slant of the letter matches the direction of the slant in the thread as shown in the Elna manual.


That's exactly where it comes from.  Holding the thread vertically, the twists will either be slanted to the right like a Z, or to the left like an S.


/          \
/          \
/          \
/          \
Z, or      S, or
left       right
twist      twist


(The left twist / right twist names don't make much sense when you hold the thread vertically, and the Z and S don't make sense when you hold it horizontally.)

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ArchaicArcane

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Reply with quote  #16 
I can believe that the thread would tend to untwist or tighten a little every time it went around a "corner" - so when it goes from the top to the front, it would take a tiny bit of clockwise twist which would have the effect of loosening the twist, then the tensioner may give it a bit of a counter clockwise twist.  The take up lever again would affect the twist then the act of traveling around the hook may be the last straw. 
It might not be a major unraveling at any one step but the loosening and then re-tightening of the ply over and over. 
Cotton generally has a very short staple (about 1/2" - 3/4" for "premium long staple" cotton, if memory serves) and thus needs a lot of twist to hold it together at all* - and if my spinning and very beginner weaving experience are any indication,  it really doesn't appreciate any loss of twist at all.  Cotton will drift apart with the smallest amount of lost twist.  It actually changes the way I weave ends in.  With wool - I can split the plies and overlap old with new and make a join look a lot less noticeable.  If I do the same with the cotton yarn I'm using right now, I end up with a pile of partially twisted fluff in my hands.

*The general rule is that the shorter the staple, the more twist it requires.  For comparison, most polyesters, etc are extruded so theoretically they're one immensely long staple, then plied for strength.

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ke6cvh

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Reply with quote  #17 
Hello group,

  Yes, I agree to the turning corner theory.  We have many many (lots and lots....like dozens) industrial double needle Singer and Juki as well as clones of walking feet Mitsibishi double needle (one).  The thread path can be tricky because of the way it will turn corners.  I started to notice one thread breaking allot more than the other and did a re-think on my thread path and sure enough it came down to the thread turning corners differently on the pre-tensioner and upper tensioner on one thread but not the other.

  Then it gets stranger.  I started to really love sewing with braided line.  I started using really thick stuff like 415 with size 27 needles and some other small sizes (relatively) like 277.  Then I started to like using braided UHMWPE and high performance PE fishing line to sew with.  The maker in USA was kind enough to answer my suspicion on the braided line.  It cannot/absolutely cannot come off the top of the cone or stuff starts to get all bunched up before it gets to the needle eye eventually causing a breakage.  Instead braided must come off the side of the spool plain and simple so the entire spool rotates.  

  The thread we use here all comes off the top of a cone but vintage thread is on the ole tiny spools.  So I'm not so sure if it matters allot with twisted thread if it exits off the top or the side but I know our Brother PE series embroidery machine was designed for spools to be held with a cap and it feeding off the top.  

  All that said if it doesn't matter so much how the thread exits the spool (top of cone or fed off side) from my observations with twisted/bonded poly thread (or maybe cones are wound differently than spools but doubt that) then it must be all in the corners being turned.  Mrs. here just puts cones on the floor and lets the thread feed up and around the spool pin and it works oh so well (and costs less for large spools).  

  From experience with the double needle machines and braided my perspective is to turn the corners in the right sequence on the tension discs.

Best regards,
Mike
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pgf

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Reply with quote  #18 
Quote:
I can believe that the thread would tend to untwist or tighten a little every time it went around a "corner" - so when it goes from the top to the front, it would take a tiny bit of clockwise twist which would have the effect of loosening the twist, then the tensioner may give it a bit of a counter clockwise twist.  The take up lever again would affect the twist then the act of traveling around the hook may be the last straw. 


Ah...  I'll have to let that visual percolate for a while in my brain, but I suspect you're both onto something.  I'm not sure I understand why turning the corners would affect S vs. Z differently, but I strongly suspect you're onto something.  Especially since, as you say, the closer to the needle you get, the more times a thread will have to cross those corners.

paul

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Farmer John

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Reply with quote  #19 
Not meaning to dispel the corner rounding theory but...

"S" twist thread is required for the left hand head of a two headed sm, and "Z" twist thread is required for the right hand head.  I would assume that both heads would have the same amount of corners to go around.  Can I also assume that if the threads were switched on a two headed sm, both would untwist and break ????   Why, I have no idea.
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ke6cvh

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Reply with quote  #20 
I just bought 4 pieces of dead stock Singer 18u322.  Started a thread on it with pictures but it looks like nobody on the forum has one so I found a dude in Algeria that said he had one from 1980 and some other sources and videos.  This is a badged Seiko TF6.  Both have hand wheel on left.  The TE6 has hand wheel on right.  These cylinder arm machines were used for shoe vamping (sewing uppers) but are excellent for other stuff as well with their 135x17 needle system after re adjustment of needle bar if it had 16x2 needles.  I did not read anything about needing S twist thread.  

Best regards,
Mike
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Farmer John

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Reply with quote  #21 
Mike, the "s" thread use for two headed sm comes from Superior Thread Co.  Here is Dr. Bob's thread twist video...

https://www.superiorthreads.com/videos/thread-therapy/thread-twist

It still doesn't answer the reason why
John
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ArchaicArcane

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Reply with quote  #22 
Quote:
Originally Posted by pgf


Ah...  I'll have to let that visual percolate for a while in my brain, but I suspect you're both onto something.  I'm not sure I understand why turning the corners would affect S vs. Z differently, but I strongly suspect you're onto something.  Especially since, as you say, the closer to the needle you get, the more times a thread will have to cross those corners.

paul


The act of curving around the guide to go from the top of the machine to the front would cause a lessening of the ply twist on one thread and a tightening of it on the other.

In fact, if I have a yarn that's a little too hard to break by hand - I untwist the ply twist just a tiny bit and can snap it by hand.  (Don't try this with linen/flax or hemp!  You will most likely be cut!) Ply twist provides strength.

I'm visualizing the final twist around the hook giving the thread that extra bit of loosening that allows the tension of the machine to snap the thread like I do by removing ply twist.

This link talks about hand embroidery thread - but the principles are the same.  You can see how the ply twist loosens with certain stitches and how the Z and S twisted threads behave differently. 
https://www.needlenthread.com/2011/01/s-twist-vs-z-twist-embroidery-threads-stitched.html

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Phyllis1115

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Reply with quote  #23 
I am awaiting the arrival of the S twist thread. 
The threading pattern of the machine may influence how the Z twist or S twist reacts while stitching.
I very much feel that each type of thread was designed to suit a need -- straight stitching, manual machine embroidery, hand embroidery, basting, etc from a wide variety of fibers. Our foreparents were sufficiently intellegent to design a working sewing machine. They also were sufficiently intellegent to design threads appropriate for all manner of uses. 


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ArchaicArcane

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Reply with quote  #24 
Quote:
Originally Posted by ke6cvh
Hello group,

  Yes, I agree to the turning corner theory.  We have many many (lots and lots....like dozens) industrial double needle Singer and Juki as well as clones of walking feet Mitsibishi double needle (one).  The thread path can be tricky because of the way it will turn corners.  I started to notice one thread breaking allot more than the other and did a re-think on my thread path and sure enough it came down to the thread turning corners differently on the pre-tensioner and upper tensioner on one thread but not the other.

<snip>

  The thread we use here all comes off the top of a cone but vintage thread is on the ole tiny spools.  So I'm not so sure if it matters allot with twisted thread if it exits off the top or the side but I know our Brother PE series embroidery machine was designed for spools to be held with a cap and it feeding off the top.  



Some companies will swear that cross wound thread (usually on cones) needs to come off the top or the drag of the cone is too much.  They'll also say that stack wound thread should come off the side - and the spool should turn as the thread unwinds, or it imparts too much twist. (Think of toilet paper coming off the roll - take it off the end and it adds twist.)  Sensitive threads, like metallics will misbehave this way.  


I mostly put stack wound on a thread stand if the machine I'm using only has a vertical pin because if I'm sewing fast, it doesn't launch the spool across the room.  I can't say my machines have ever been this touchy about thread - even my long arm that I can really get moving uses S or Z twist thread equally well.

So, the thread path for the side that uses the S twisted thread - does it basically mirror the Z twist side?  I haven't had a machine like that on my bench and the pics I find on Google are not clear enough for me to tell.




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ArchaicArcane

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Reply with quote  #25 
Quote:
Originally Posted by Farmer John
Not meaning to dispel the corner rounding theory but...

"S" twist thread is required for the left hand head of a two headed sm, and "Z" twist thread is required for the right hand head.  I would assume that both heads would have the same amount of corners to go around.  Can I also assume that if the threads were switched on a two headed sm, both would untwist and break ????   Why, I have no idea.
John


I think that's exactly right. 
It's likely not the number of corners it's making but the direction of travel around the corners.
My suspicion is that the thread path for the S twist side is designed to further tighten the ply twist and the thread path for the Z twist side will tighten its ply twist.  If the machine calls for S on one side and Z on the other, then yes - I would guess that both would start to break if they were swapped.

I can do a deep dive into spinning theory to explain the twist and how it affects strength if anyone wants - but I don't want to if it will just muddy the waters.

The executive summary version though is first a singles is made (this would be the "2 or 3 ply" that you see on labels) and then they're plyed together to make the final thread or yarn. 
2 ply would imply that there are 2 singles twisted together to make a plyed thread.

So to make the singles out of fluff, twist is added in the Z direction (clockwise).  This is the "primary twist" that Dr Bob talks about in the thread therapy videos.  This creates a relatively fragile thread that would likely never run through a sewing machine tensioner or needle without breaking.  It also would shed a lot.

So to create strength, multiples of these singles are grouped together to share the load.  But 2 or 3 threads that are not plyed together are not much stronger - so we ply them - or twist them together to create a much stronger thread than they would be as 2 or 3 singles alone.  This is the "secondary twist" that Dr Bob talks about.  Spinners usually refer to it as ply twist.  This twist is in the opposite direction of the "primary" twist - so if our singles were spun z, this ply twist would be spun S (counter clockwise) . So the finished yarn or thread is referred to as an S twist thread/yarn. One could apply Aristotle's comment about the whole being greater than the sum of its parts here because this thread becomes far stronger than the singles.

Edited to add: This is especially true because the act of plying the singles together removes a little bit of twist from each singles - making them weaker than before they were plyed and thus very dependent on the ply for strength.

These threads and yarns can be very strong once plyed but if the ply twist is undone even a little they can fairly easily be broken because the strength is lessened greatly vs the original plyed thread. Adding ply twist would make it harder still to break the thread (to a point of course.  At some point the stresses would be too high and the thread would snap but that's well out of the scope of what a thread path should do.)

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Reply with quote  #26 
Quote:
Originally Posted by ke6cvh
I just bought 4 pieces of dead stock Singer 18u322.  ...  I did not read anything about needing S twist thread.


According to the manual I found for the 18U322, it says to use left twist for the needle, but either left or right twist can be used in the bobbin.  According to the manual for several 18s, it says for 18-25, 18-26 and 18-36 (which evidently use two needles), use right twist for the left needle and left twist for the right needle and either twist for the bobbin.

Janey

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ke6cvh

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Reply with quote  #27 
Dr. Bob's video is great but he is just plain wrong when he talks about the small rod never needing to fit the inside diameter of the cone.  He is teaching to users of domestics sewing machines and embroidery machines in a certain range of uses and does not talk about machines needing extremely consistent/un-changing tensions that are dialed down.

This may be true with machines with higher tension settings but not true with machines that have lower tension settings.  The best example I can give is the art of warping a beam with a loom.  It really is a case of GIGO (Garbage In Garbage Out).  With an industrial setting for beam warping the operator is not going to understand the science behind it.  But with small production weavers or home weavers there is many variables (unfortunately also these variables are coming from the mgf. of the loom).  For example, our 12 shaft countermarche with flying shuttle and dual warp beams has been set up to warp from the rear using a method I learned from studying literature and specifically literature written on the subject in books purchased carefully.  For the width of the beam I need 30 feet minimum of warp length going onto the beam.

So what does that mean when comparing to a lowly cone of thread?  It is all about angles.  Some cones are cross wound with a tapered top as part of this solution.  This is why I like the way the Mrs. here puts the cone on the ground.  We go as far as DIY caps on top of the cone to make the thread have an angle away from the cone from both top and bottom as it unwinds but this also introduces an entirely different level of problems because if there is drag as it goes on this cap it will cause it to get wound around the stem of the cap.  

And....to the mis-centered cone where the angle is different coming off one part of the circumference of the cone as it is another part because the hook at the top is now not centered to the spool.  This causes a very subtle change in tension as the thread exits the spool.  How do I know this???  Because with some of our industrial overlocks the looper thread is sometimes very low tension.  If the tension is dialed down on the looper and it is also changing then what occurs is an overlock stitch that literally varies at a directly proportionally rate as the thread travels around the un-centered cone.  

Do I have this problem with heavy hitter stitchers?  Absolutely not because a small change in tension coming off the cone compared to an already high tension setting will make no difference in performance.  If one is using a spring fed feed and dialed it down super low so that stretch can be sewn on knits (Like the blogger Elena does on her 48k) then changing tension (in this case the needle) can make a big difference.  She reports 60 percent stretch on her knits when using the 48k.  I'm uncertain but am guessing this is not with stretch thread.  What I do to help things out on my overlocker lately is to use bonded poly in the needle and wooly nylon in the two loopers that has a little stretch as well as an awesome coverage on the edge of material.  With care I now get the most amazing 3 thread when overlocking using a size 11 needle.

With other machines using heavier thread (example ticket 80 in loopers and ticket 50 in needle or if heavier ticket 30 in needle and 50 in loopers) I discovered the hard way on my older Union Special 39800 5 thread I was experiencing broken threads to changing tension as it unwound and travelled it's thread path.  

So what I'm saying is if a machine uses a looper wether it be a waist band, an overlock, felling, flat seamer (we have all these and more) thread path is huge.  A gent I know who works in a factory said they are using nails for the spools and the spools are literally vibrating around....not a good thing.  I really like the old school thread stands.  My favorites are Merrow but even some of the Union Special and really old Singer are no exception and usually they can be ID'd immediately by the cast iron used.  The thread travelled far above the cone before going over and out to the machine....but the drawback is now one can't use a fan to help ventilation?  

The devil's really in the details wether it be warping a beam or achieving consistent quality and eliminating broken threads in a machine with a looper or tensions dialed way down for stretch applications.

Best regards,
Mike
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ke6cvh

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Reply with quote  #28 
Hi Janey,

  Wow!  Thanks for the link on the manual...I've been looking for one.  And....you confirmed my suspicion on double needle machines with left/right twist in different needles left/right.  I get around this myself on our double needles currently by entering off the other side of tension disc and then wrapping around the pin that goes into the groove of the disc.  Basically I then enter each tension disc from the same side and with the thread entering and exiting with more of the disc "grabbing" the thread I get a more consistent thread.

  With Union Special machines the center rod for the discs has a groove in it.  What this does is to force the thread to enter and exit while going through the center and not being able to wander out of that position.  With our 45k1 machine the thread is wrapped more than one revolution around the tension disc which achieves this same thing while getting higher tensions.  From my observations if the thread is given an opportunity to wander in it's position as it travels through it's path in the disc that spells trouble and the way to eliminate that is to get a larger angle (example entering at the 2 o'clock position and leaving at the 3 o'clock position vice entering 1 o'clock and exiting 5 o'clock).  The only way around this larger percentage is the hook in the center shaft that causes it to travel through the center shaft like the Union Special overlock machines do.

  Then there is the science of pre-tensioners and where they are placed in the thread path 😉

Best regards,
Mike
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ke6cvh

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Reply with quote  #29 
regarding there being a difference between S and Z.....I have a portable thread winder that runs off a 9v and is pretty darned great/good.  I spoke to the designer and he was making a series of stuff for winding bobbins in the USA.  He said to me he used to be a thread person at the NJ plant a long time back.  If Singer was willing to have positions for thread experts that means there was allot of effort and research that went into it.  If they recommended the differences between left and right twist for machine applications and some are getting away with both types then possibly the needle they are using is a little more forgiving in the eye area and they are using a heavier tension?  If it is causing problems maybe that is when the eye is close to the smallest allowable for the thread and the tension is dialed down?  For ticket 30 I will use a size 19 needle even though it's harder to get here.  The local tailors use size 14 needle for tex 24/ticket 120 even though the tables specifically state that size 11 is the correct size needle to use with it.  With the absolute match (which also can be determined by material thickness/tension settings) between needle and eye size as well as needle diameter might make a big difference.  In some cases heavier thread just can't be used because the knot is too big for the thickness of the material (which one of the many reasons why I like the triple stretch stitch so much allowing me to bend the rules to get super strength and stretch on a smaller thread/needle).  

Best regards,
Mike
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