Understanding Thread Weight
Good Morning, Quilters!
Today I hope to provide a better understanding of thread weight. It is an important topic as choosing the right thread can be the difference between great and disappointing results when machine quilting!
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Thread Weight is Confusing!
The thread weight numbering system is counterintuitive because as thread gets heavier or thicker, the number gets smaller.
For example, 40 and 28 wt thread, the thread I like to use to create focus motifs, is thicker and heavier than 50 wt thread I use in the bobbin.
So let’s talk about why.
To clarify, I’ve added a few sketch notes to help illustrate.
Fixed Weight Measurement
Thread is measured on a fixed weight system.
A fixed weight is placed on one side of the scale and then thread is added to balance the scale.
Length of Thread is the “Weight”
Next, the length of thread required to balance the scale is measured. This is the thread “weight”.
Thread weight is really a length!
The weight number you find on a spool is the length of thread required to achieve a fixed weight.
As you can see, it will take a longer strand of thin thread to balance the scale than it will a thicker thread.
Why Thread is Important
For quilting, we use thread to achieve different goals. Sometimes we want to create focus motifs and other times we are trying to develop texture. Heavier threads will create a more visible motif, while lighter threads will produce a better texture or background effect. It is essential to choose the correct thread weight for machine quilting.
Next week: Choosing the Right Needle
I hope this helps!
Next week, we’ll have more from my notebook.
Please let me know if there’s a topic YOU would like me to cover!
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33 responses to “Understanding Thread Weight”
Lori, since you’ve switched to your new platform, I am receiving 2 copies of your blog regularly. I didn’t see any contact info on your website, so I have posted it on your blog. Can you delete one instance please. Thank you in advance.
Thanks for letting us know!! We will work on correcting that!
Me too…. two copies some days and none other days… BTW, I really don’t want to sign up for instagram… already can’t keep up with phone, FB and email. I loved opening up to The Inbox Jaunt every morning..Thanks
I received two copies also!
I’m also in the “two a day” club!
This post really helps to analyze the concept of thread weight. Thank You! I have just started the “spools of thread” sampler that you did in Feb 2015 – what fun! However, you might want to know that the links for this sampler in the mystery quilt-a-long section of your new website don’t work. Since I’m a very visual learner, I can figure it out anyway and am learning a lot in my process.
Hi Karen – thanks for letting me know! I think I’ve figured out the problem – try using this link: https://lorikennedyquilts.com/evidence-and-deduction-the-mystery-quilt-a-long/
I’ve also added them to the “DIY” section under “Projects” at the top. You’ll have to click to Feb 2015, but they should all be there!
I love checking out what you are teaching and sharing…
This was a very clearly articulated explanation on thread weight – thank you; it makes great sense once you described how the numbering system originated.
If you ever have the time, I would love to see a visual difference of the same motif quilted using two different weight threads; that would be wonderful.
Why do you put a lighter weight thread in the bobbin? I’ve always put a heavier weight thread in the bobbin. I understand that a lot of this is your machine and tie personal choice, but I’d there a technical reason you do this? 😊
I hate auto-correct …
It should be: I understand that a lot of this is based on your machine and personal preference, but is there a technical reason you do this?
I would note for your reply that a 100wt thread in the bobbin instead of 50wt puts more thread on the bobbin so changing the bobbin is required less often. Now that I read the note on how thread is measured, it looks like that might translate to twice as much but the thickness of the thread might have something to do with filling the bobbin also. I even notice that different brands of thread with the same weight (50wt for example) look to have a different width. I try to use the thinner brand in the bobbin to get as much quilting in before I have to refill the bobbin.
This is fantastic! I went to a lecture by Alex, the owner of Aurifil and he never talked about this – that the weight is the length.
I love your posts and your books, thank you. I am excited for you and your new webpage. Good luck. I hope you don’t mind me saying that I find it much more difficult to read your posts now because of the non-moving flower motif in the background of your posts. it is like two separate visual messages, the motif and the post. It might not be so distracting if the motif moved with the words? Not sure but just thinking…
I also am having problems with the background. Thought it was just my motion sickness coming to life. Might be but do without it.
I agree about the difficulty the background poses. It’s quite annoying.
Very helpful. Thankyou for posting this information about thread weight. I always enjoy your teaching tips.
I love your ideas, and this one really sounds like a winner reference tool. I tried to follow the link you gave to Karen on April 4th, and that link leads to a dead page. Was sorry to see that. Thanks for all your attention to detail and clear instructions. Just what we ( mostly of all “I”) need!
I am also in the 2 copy group!
2 copy group – me too
Hi Lori, I also am getting 2 posts of your blog. Could you delete one please? Thanks. Really enjoy your posts!
I thought this was really helpful. I also get two copies of your email. I also wanted to mention I find the background distracting – there is no white background box for your post, it’s just floating on your lovely scrolling flowers. Makes it hard to read the text. I can read the comments easily because they are all on white boxes.
I’m in the 2 email group too!
Interesting the comments about the background being distracting. I didn’t even notice the background until people posted about it today! I use an iPad Pro to read the posts so don’t know if that makes a difference. 🤷🏼♀️
Thank you for explaining this mystery!
Very interesting about thread. My pet peeve is they don’t put wt on spool so I don’t know later on if it’s 40, 50, 60 wt. any suggestions. I notice some are different color spools but don’t know what’s what.
Ah ha now I will remember this without having to google every time – thread weight is really a length!
I love your explaination. It is so much easier to remember something when you understand the reasoning behind it. But some threads are sold by Tex not weight. How do I relate tex to wt?
Ps. I’m not having any trouble reading your blog on my ipad…flowers are very faint and the background scrolls with your words, as if it was typed onto wallpaper. I wonder if problems are related to the readers device and software?
Not part of the two mail group so don’t delete one or I will have none!
Quite some time ago I heard a great mind peg for thread weights. It was probably on Fons & Porter Love of Quilting. Here it is:
Picture threading a needle with multiple strands of thread. Now pretend the number of strands that will fit through the eye of the is the same as the weight number listed on the thread spool or package. Example: 100 wt. thread can be thought of as 100 strands of thread fitting through the eye of the needle; and 60 wt. thread can be thought of as 60 strands of thread fitting through the eye of the needle. Therefore you immediately remember that 100 wt. is much finer or lighter than 60 wt. because more strands fit through the eye of the needle. Try another example… 50 wt. vs 30 wt.? Answer: 30 wt. is the thicker or heavier thread because only 30 pretend strands fit through the eye compared to the lighter 50 wt. I do not know if this same concept works for crochet thread, pearl cotton, etc.
I really need this teaching about the numbers… thread and needles.. I get it confused and have to reassess each time with new projects. Thank you for this !!
Like Karen from April 4th, I would like to give your thread weight/spools of thread mystery quilt a try. The link you provided, however, does not give any instructions for the quilt, and the links to your old website no longer work. Would it be possible to get those instructions? Thanks so much!!