Playing with…thread weights

Do you ever get confused by the different types of thread and when to use them? Find yourself always using the same thread because it’s the “safe” option? Read on for my thoughts and tips for some of the thread weights most commonly used in patchwork and quilting.

I do need to start by saying this list is far from exhaustive. As well as the weight of a thread, what it is made of is also relevant. Everything I’m talking about here is based on 100% cotton thread (Aurifil brand to be precise) because that is what I use more than anything else. I prefer it but that genuinely is a personal preference; I know plenty of people who only use synthetic threads because that’s what works for them.

I’m also only going to talk about thread uses for machine pieced patchwork and quilting. There are many other uses for these threads (garments, bag making, hand piecing, appliqué etc etc) but I mostly know and sew patchwork so that is what I’ll be sticking to for this post.

We’ll start from the thickest and work down to the finest. Generally speaking, the larger the weight number – the thinner/lighter/finer the thread weight.

12 wt

I’d say the best-known use for 12wt (and how I use it most often) is for hand quilting. I’ve never got on with hand quilting needles (the needles are too short and the eyes too small for me!) so for hand quilting with 12wt I use a size 9 embroidery needle.

But 12wt can be used for machine quilting too. This isn’t for the feint-hearted as it is harder to get it looking smooth and even but it does give a lovely effect for both straight line/walking foot quilting and free motion quilting. My top tips if you want to try 12wt for some machine quilting are to use a 90/14 top stitch needle, have 50wt in your bobbin and slow down!


Much like 12wt, 28wt is mostly intended for decorative features but gives a slightly “lighter” or more subtle look.

My tips are the same as they were above; size 9 embroidery needle for hand quilting, and 90/14 top stitch needle, 50wt in your bobbin and go slow for any machine quilting.

Personally I prefer the look of the heavier 12wt for hand quilting but when it comes to free motion quilting I found the 28wt a bit easier to work with but still giving that heavier-than-usual look.


The only thing I use 40wt for is machine quilting. I love it for straight line/walking foot quilting, especially if you want to really make a feature of your quilting as it stands out that little bit more than the slightly lighter 50wt.

When I was sewing the samples for this blog post, this was the first time I had tried free motion quilting with 40wt. I really liked the effect and found it no more difficult than FMQ with the more-usual choice of 50wt.

I’d recommend using a 90/14 top stitch needle with 40wt in the bobbin.


The work-horse, the all-rounder, the jack of all trades (and master of most!) is 50wt.

I use 50wt for all my machine-based patchwork piecing using a 80/12 Universal needle. For me it is the right balance between being heavy enough to have strength but light enough to not add bulk to my seams.

When it comes to machine quilting, 50wt is my usual “go to” for everything; stitch in the ditch, straight line/walling foot and free motion quilting. For all machine quilting I use a 90/14 top stitch needle with 50wt in the bobbin.


And finally we are at the lightest/finest weight of thread I’m going to talk about.

In all honesty, this was a bit of an experiment for me too as I don’t use 80wt very often but I want to see how it did with a few different use I thought might be good. For machine quilting I used it with a 80/12 Universal needle (although a Sharp would have bee good too) with 80wt in the bobbin. I loved 80wt for stitch in the ditch because it really melts into the fabric making it a more subtle look than 50wt. And it was the same for straight line/walking foot quilting. I was worried 80wt might snap when free motion quilting but I went slightly slower than I would do when using 50wt (although not as slow as I did for the heavier threads) and I was pleased with how to looked.

Like 12wt FMQ not being for the feint-hearted, I’d say the same for 80wt but for a different reason. As the thread is so fine, it really shows up any inaccuracies and mistakes!

One last quilt-related sewing technique I haven’t mentioned yet is hand sewing the binding. 80wt is my top choice for this as it is so fine. I use size 10 Milliners needles for binding hand sewing as they are super long and sharp!

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