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Jun 20, 2011

"Are my seams straight?"

Readers, we're not going to talk about ladies stockings today, though I haven't ruled out this riveting topic for the future, perhaps during "Fetish Week."

No, today, I want to discuss the tricks and tools we sewists use to keep our seams straight and seam allowances accurate.  MPB reader "E" recently emailed me to ask how I manage to sew so evenly, and whether it was simply a question of practice.

It does take practice, certainly, but there are lots of tricks you can use to make sure you're sewing accurately from the very beginning.

Here are a few of the most popular ones:

First of all, most sewing machines come with a numbered throat plate (sometimes called a needle plate).  The numbers on it refer to 8ths of an inch.

My vintage Kenmore 158.141 has markings on both sides of the presser foot (not just to the right).  Isn't that fantastic?

Vintage Singer straight stitchers often did not come with numbered throat plates (don't ask me why).   Here's my Featherweight.

Jenny at sells numbered replacement plates for many vintage machines.    I use one of the ones she sells for my Singer 15-91, which did not come with a numbered plate.  It works fine.

Jenny also sells numbered peel-and-stick decals which you can adhere to a plain throat plate.  They need to be trimmed first and lined up carefully, but they do work well, and they're cheap and replaceable.  I use one of these on my Pfaff 30.

The most popular seam guide is the old screw-on kind.  That's one of the things those little holes on the bed of most vintage sewing machines are for.

I don't own one but I do have a photo of how they work.  Very straight forward.  Of course, it helps to have a numbered throat plate so you know where to line the guide up.  Otherwise you have to measure from the needle to the outer edge of your fabric, the width of your desired seam allowance.

Whether or not you have a numbered throat plate, here are a few more helpful tools.

I poo-pooed this magnetic seam guide recently, but other people like it and find it helpful.  This is another tool that's easier to use if your throat plate is numbered.  If it's not, you'll have to measure.

When I'm using a vintage straight stitch machine, I use the straight stitch foot as my guide for topstitching.  The right edge is 1/8".

The left edge is 1/4".

(I have also discovered that the far edge of the throat plate screw is 3/8" and the inner edge of the large hole is 5/8".  Sometimes those are the only guides I use, but I don't recommend this for beginners.)

My zigzag machines all have low shank adapters that use the same snap on/snap off feet.  You can buy sets of these on eBay.   (High shank adapters use the same feet, btw.)  Two edge guide feet that are very useful for accurate topstitching are these:

I discuss them at length in my topstitching movie, which can be viewed here.

Friends, have I left out any useful methods of sewing straight seams and accurate seam allowances? I've heard of some people using tape to mark the measurements but don't all the different tapes get confusing -- and gummy?

Which is your preferred method?

(A master sewist I know marks all his seam allowances in chalk, eliminating the need for guides altogether.)

Please share your secrets with us today -- we won't tell!


  1. I use a small post-it note. Easy to see, and easy to remove. You can also use a whole post-it notepad. Take off the brown paper backing so the pad can be stuck to the throat plate.

    But more and more, I'm using the chalk-marked (or asted) seam line. It takes more prep time, but it makes the actual sewing more pleasant, and the results are better.

  2. Oops, I meant to say "basted" not "asted". :P

  3. I'm a fan of informal guides such as the edge of the presser foot or some other landmark. I use that more than the etched measurements on the needle plate.

  4. I also use the marks on the plate and even the edge of my machine feet. One thing I think it's useful is to keep your eye on the edge of the fabric, to make sure it is following your guide, whatever it is. We tend to look at the needle working, which may move your fabric away as you're not paying attention to it. I'm planing now to get a presser foot with the edge guide.

  5. I agree with Sandi, using the edge of the presser foot works well, especially in conjunction with an adjustable needle position. I like to keep as much fabric on the feed dogs as possible for even sewing, and when you are doing edge stitching moving the needle is the best.

    I have an European sewing machine so all the throat plate marks are in centimeters. I've converted as much of my sewing as I can to the metric system, which helps, but when I need perfect topstitching or topstitching a wide distance from the edge, I pull out the post-it notes. If a project calls for multiple wide widths, out comes the masking tape. It all works.

  6. I like to use the edge of the presser foot most, although I also have to use the throat plate (as I now learn it is called!). I think a lot depends on the sewing machine too though. I could never overstitch or flat-fell properly with my old sewing machine as I was always falling off the edge or veering off. Its replacement however sews fabulously straight.

  7. i've been known to use a quilt guide when topstitiching. Mine is all metal which is a little different to the one in the pic

    I also mark all my seam lines on the wrong side of the fabric with sewing carbon paper and a non-perforating wheel marker.

  8. oops the link doesn't work. try this one

  9. I am in awe of people who mark all their seam allowances!

  10. I use my presser foot and the throat plate, but my question is about stitch length and speed. Do you adjust your stitch length from standard seaming setting before you begin top-stitching? Also to stitch at a slower speed when top-stitching?

    I am a perfectionist, so top-stitching drives slightly crazy! LOL!

    I need help!

  11. Melanie, I generally topstitch with a slightly longer stitch, but the length really depends on what I'm stitching (longer for jeans, shorter for a shirt collar). Sometimes I loosen the top tension a bit too if it looks better that way.

    I DEFINITELY sew slower, OMG, yes. The great thing about those old Singer sewing machines is that they do not race and are easy to control.

  12. An old quilters trick is foam tape. Once you've placed the adhesive side down you have a high ridge that's hard to ignore, making it easy to do miles of straight seams. And it peels off fine.
    Masking tape works too, but that means you have to look at what you're doing. ;-)

  13. sewing for 30+ years I can stitch by eyeballing the allowances, however for students I use the post-it note trick, works great.
    My lovely vintage Singers have the seam allowance markings.

  14. I use all of the above, depending on what/where I'm stitching. Most used are my edge feet because I can zip along faster with those. But sometimes the rudder gets in the way so then I'll use the needle plate guidelines or the "toes" of the foot with adjustable needle positions.

    How's your mom, Peter?

  15. I measured and marked my vintage machine with electrical tape. I also use the presser foot edge as a seam guide, but I've never actually measured to see how wide it sews.

  16. I learned to sew using patterns without seam allowances, and nothing irritates me more then patterns with seam allowances included! But I guess I'm alone here :)
    I mark all seam lines with chalk and that's my only (and in my opinion most precise) guide while sewing. It may be a little time consuming, but you get used to it. Only a
    matter of habits I believe. I never understood all the fuss about seam allowances, but that's just me :)

  17. I use chark mark seam line when the seam has curves and not just a straight line. If i am sewing something which has just a straight line as seam then i use the seam guides in machine's throat plate.

    Since i self draft my patterns,they are ready patterns (no seam allowance) and hence when i chalk mark while tracing the pattern i get the exact stitch line on to fabric and then add seam allowance and dash mark the cutting line.

    This process felt tedius initially, but makes sewing process a lot more easier and error free, well mostly , but to err is human and i do end up ripping stitches but all is well that ends' well..isn't it..

    Adithis Amma, Adithis Amma Sews From India

  18. Learning to sew from my mom & grandmom, they just eyeballed it, perhaps occasionally referring to the markings on the throat plate. I thot that's "how you're supposed to do it," yet my seams often wandered & were uneven. Until I finally realized what those little screws were for & attached the screw-in seam guide. It's magic & makes sewing brain-dead easy, esp. for the long, tedious seams I tend to have in big skirts & such.

    For small, fiddly work, I tend to go by the presser foot. And there are occasions when I've marked out the seam -- usually when I've drafted a pattern myself, thus I've drawn in the seam allowances directly on the fabric.

    I think it's worth trying all kinds of methods bec. they may work in on different projects.

  19. I put blue or purple painter's tape on the plate so I have a big visual cue for 5/8" seams instead of having to watch the itty-bitty metal lines. It doesn't prevent all wandering, but it does help. For topstitching or narrow stitching, I use the presser foot as an indicator.

    I only mark on the fabric when making darts. In fact, that is the only way I've ever been able to get somewhat even darts -- I cut out the dart on the pattern, position it, and draw the lines directly on the fabric. Sometimes I still have problems if the marking pen is too light to be easily visible, but generally it works.

  20. I must be the worst sewer ever. I use all of these guides mentioned and somehow I still don;t have perfectly straight seams. I generally use the "if it's fine from 3 feet away, it's fine" rule, but I'd really love to have straighter stitches. *sigh*

  21. Awww, not going to have a stockings tutorial?


  22. Foam tape! Magnets! Brilliant! I mostly eyeball it using a variety of landmarks.
    Maintaining a steady speed helps. Also my Janome has a see through perspex foot that makes straight sewing a lot easier.

  23. Aw, Peter, I'm so sad we weren't going to be reading about seamed stockings today! ;) After all, that is such a gorgeous pic of ?? (Betty Grable? I'm no sure...). lol.

    Love this post--I'm adding it to my list of posts to link to in Sunday's links roundup! (If you don't mind, of course...)

  24. I'd be honored, Casey! Yes, that's Betty -- or her twin sister, Batty.

  25. Debbie, my mother is doing well, though still in rehab (till tomorrow). Thanks for asking!

  26. My Pfaff has an adjustable needle. It can be set for left, right, and center. When set to the right, if I sew with the edge of the fabric lined up with the edge of the foot, it's exactly 1/4 inch. The middle is 1/2, and the left is 5/8. So while I *do* have a numbered needle plate, I know exactly where the needle needs to be to get the seam allowance I want.

  27. Ooooh, you finally brought me out of lurking with this post. I sew on an old Viking Special 21A, from 1961 I think (it was free, from my Great Aunt). I have been using painters tape for 5/8 seams since there are no markings on the throat plate and no good references on the machine for that one. You motivated me to look in my accessories box, and what do you know, there is a seam allowance marker in there. This one is not like any of the ones you've shown. This one is a bar that slides through the pressure foot post with a little leg that hangs down. When I raise the pressure foot, this things goes up with it. I never knew I had such a thing. Thank you. Now I can stop looking at that ugly blue tape on my beautiful old green machine.

    On another note, make sure your Mom does her excercises everyday when she gets out of rehab. The hard work will pay off in no time at all. My mom had her hip replaced two years ago. She is so much more mobile now I have a hard time tracking her down some days. :)

  28. I am also with Peter: I use most the troat plate lines, but when I work with my Featherweight I use the seam guide and it works perfect. I have never marked line with chalk and it comes out just right.

    For perfect topstitching I recommend the video that Peter did in his Singer 66 treadle! Since I saw it, I have no trouble to have clean topstitch lines! Thank you so much for sharing!

  29. I've been thinking about this topic myself lately! For some who use all the methods you mentioned above and still don't have straight seams, they may want to look at how they're cutting the fabric, actually. If you're using the cut edge as a guide to sew by, but your cut edge isn't perfectly straight, then your seam won't be, either. This is where the marked seam line works really well, because it's much more direct (and you can cut as quickly and sloppily as you like, LOL). Personally, I just use the markings on the throat plate or my presser foot (which actually has some of it's own markings on it), but I've also figured out lately that (for straight seams anyway) I don't need to control it quite so much as I have been. The machine will sew a generally straight line, I just have to keep it on course.

  30. I have a Pfaff with the move-able needle and it is brilliant for getting the seams straight while just lining up with the foot.

  31. Hello Peter,
    First off I just wanted to say you have a wonderful blog, very entertaining and educational. I use many of the above methods (edge of presser foot, throat plate markings, screw-in seam guide) depending on how difficult of a seam I am sewing.
    I love how your Kenmore has markings on both sides of the throat plate! Just a few days ago I modified my own throat plate to have markings on both sides, using one of those decals from Sew-Classic. Of course, most of the numbers are wrong, so I wrote over them with a permanent marker, but it is incredibly useful to have those markings on both sides.

  32. No matter what method you use, I think the key thing is to have the accurate stitching where you need it and not to worry too much where you don't! Pants inseams or underarm seams of a stretch fabric top -who's going to notice a mm or 1/8" deviation there?

    I'll definitely give the traced seams a go on my next princess seamed waistcoat- the last one took massive concentration - but on the next loose knit tunic I'll just go on using the foot as a guide, getting the occasional small wobble and using Noelle's three foot rule!

  33. Anonymous,
    The "seam allowance marker" you talked about is actually for quilting. That "little foot" you spoke about goes into the ditch that the previous stitching made so that so that the next line of stitching is perfectly parallel. But, I'm now going to use it just as you suggested. What a great idea.

  34. i like to use the presser foot edge because the lines on my machine in centimeters as someone else mentioned, i'll have to try some of the suggestions mentioned above. Peter, you are so funny and charming, i never leave here without a smile on my face, thank you!

  35. I also sew on a 15-91 with no markings. I put different colors of electrical tape at different widths. It works for me for now, but I may try one of the seam guides just for fun. Thanks for another great post!

  36. Unfortunately none of these methods will help you one bit if your feed dogs are off or your fabric is a slippery one.

  37. Hi! First time reader and commenter! Newish sewer. Hello!
    I use the inside and outside edges of my presser feet as guides, the etchings on my throat plate, and masking tape to help me sew darts seen here:

    I also recently tried my hand at quilting using masking tape as a guide:

    As a side, I also recently tried using it as a "template" for cutting bias strips from very slippy material. I stuck strips of it at 45 degree angle across the grain of my fabric. Not only was it the perfect width to act as a cutting guide, it also held the fabric steady whilst I was cutting

    Masking tape truly is the WD40 of sewing!!

    BTW, I love your affable style of writing. Just fab. :)

  38. I tend to use the markings on the throat plate as a guide but having sewn for some years now I can generally do it by eye.

    A few tips for beginners that would have helped me when I started out:

    - Make sure you take time to adjust your fabric to the left of the machine... what I mean by this is every so often re-organise the material so it's not dangling off your sewing table and pulling at the needle. This will make sure that you are more in control and not 'steered' of course by escaping fabric:)

    - I also find that it I only lightly handle the fabric that is running into the machine and out the other side, the machine (if working well) grabs things evenly. I find a light touch works really well when doing curved seams.

    - Don't be worried if you start off slow in order to get nice straight seems - it's not a race and you'll get better with time!


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