Seam Allowance Curve Ruler

As I down coffee after coffee and scurry about with watercolor pans and digital painting tools in the background, I deigned it high time I finally cross off an item from my “must-write posts list” (lists breed like bunnies in my notebooks).

One of the distinctions of Japanese patterns is that seam allowances need to be added. I know that this is often a turn-off for many folks, but I happen to love it. There’s something about adding that extra 1 to 3 centimeters to the traced pattern pieces that I find very soothing. I’m probably weird, though.


So a few months ago, the always knowledgeable June pointed me in the direction of the SA Curve Ruler. Before I had a chance to check out the link, however, the owner of the company contacted me to see if I would like to test them out. I said yes, of course, because c’mon — a ruler that would make adding seam allowances a piece of cake? No brainer.

I received the 3/8 inch mini and pattern drafter (3/8 inch = 1 cm, and most Japanese pattern seam allowances are 1 cm). I think the concept is genius and I really wanted to fall in love with them. In all frankness, they haven’t revolutionized my life, but I like them a whole lot. I’ve been using them for some weeks now, and there are many obvious benefits. The idea is that you can slide the the ruler along the pattern edges for a quickie seam allowance addition, rather than the connect-the-dot system I usually use. With both the mini and pattern drafter, you’re pretty much covered for all curves and straight lines.


The main problem for me, though, is that I have chubby fingers. The 3/8 inch ruler is…well, only 3/8 inch wide, and I found it challenging to hold the rulers down properly. My fingers keep getting in the way. Also, it was a little cumbersome to have to switch between rulers and there wasn’t an easy way to create certain seam allowances larger than 1cm (1.5cm, say) since I didn’t have the metric version. An easily solvable situation. I do find it very helpful for straight sides and use them often for that. And I see a lot of potential for pattern drafting. The curves are still a little tricky for me, but like with anything, with practice it becomes easier to use. I like the design, the way the rulers are clear, and the concept itself is fantastic. I bet the 5/8 inch would be perfect for Burda patterns.


I did let Claire, the owner, know that it would take me a while to post about the rulers, but now I’m very sad that I took this long to talk about them. She seems to have decided to shut down her company, though she is still selling her rulers through a few venues. I did promise to review them, so I wanted very much to honor that. I really do think the rulers are great products with multiple uses. I am so appreciative of and impressed with women taking risks and forging ahead with businesses. I hope another venture is in the works since she’s very ingenious and talented!

15 thoughts on “Seam Allowance Curve Ruler

  1. Just bought my first European pattern without seam allowances. (At the risk of sounding unsophisticated) I’m annoyed! Would you mind sharing how you added the seam allowance before you received these lovely curves?

    1. Hi Kristi! For the most part, I still use my old method which is basically measuring out the seam allowance width every couple of inches next to the traced lines. So for example, if the SA is 1cm for the armhole curve, I would measure out 1cm from the top of the shoulder and make a little dot, then I would make another dot 1cm out about two inches down the curve until I have a bunch of dots that I then connect. If it’s a straight line required like the side of a shirt, I would add two dots about 10 inches apart and draw a line (or use the SA ruler). Does that make sense? I’m happy to provide a visual later too, if that would be better 🙂

  2. That sounds helpful. I use the book, sewing clothes kids love a lot and it doesn’t have seam allowances. This is probably horrible but since nothing I’m making is a tight fit I always just eyeball it! I think I’m pretty good at eyeballing the 3/8 SA that I love! Occasionally I forget though and someone gets a little snugger fitting shirt!

    1. Ah, the eye-balling method…I’ve used that too! I tend to use that method when ironing up hems before stitching…;-)

      1. actually until I got my grandma’s fancy hem measuring thing I totally did that too. I happen to love this thing… it’s an oddball shape with every hem length you can imagine. You perhaps have one… it’s so cool!

  3. I hate it when I find a great product and the company shuts down, especially with the huge resurgence in home sewing.

    I’ve used magnetic seam allowance guides in the past, stick them on your scissors and cut away:

    They work quite well, without all the measuring and eyeballing.

  4. Hi, The problem with sewing helpers is that I can’t ever find them when I want to use them. Do you know where Suburbia Soup went? Or did my computer just lose it? Thanks, Greta

    1. Ha, I’m forever trying to find things I’ve misplaced! As for Suburbia Soup, I don’t know what happened to Venus. I checked her blog and you’re right, it’s gone!

  5. A very fair and honest review, Sanae. Thanks for sharing it! It sounds like a great tool. I usually add a half inch SA to my patterns b/c that’s where my machine’s needle is from the edge of the foot where I line my fabric up to. For straight edges I just use my clear quilting ruler and for curves the same “connect the dots” technique you mentioned. Oh, and the occasional eye-balling thrown in for good measure:)

    1. Wow, that’s a cool tool! I don’t use my rotary cutter that much unless I’m cutting knits, but I can see how handy that could be. Thanks, June!

  6. Hello!
    I’m Austrian, so I’m used to adding seam aalloances 😉
    I use a flexible curve ruler
    like that
    BUT I don’t use it to measure, but I take the wideness (I dont’ know if this is the correct english word).
    Mine has 1,2cm, so I got used to sewing with 1,2cm seam allowance , even on the straight lines (but that I do with a regular ruler, that’s faster)
    The curver ruler is made out of rubber material, so it won’t slide away.

    1. Oh, this looks interesting, Angelika! I had something similar a long time ago, though I have no idea where it is now. I can see this being very handy for the curvy bits!

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