Sewing Back-to-School: Stitches & Tension

This post is part of the Sewing Back-to-School series, 30 days of helpful sewing articles by guest bloggers. Feel free to check out the original Sewing Back-to-School post for schedule and previous posts!
Ali is a terrific seamstress, and her blog recently got a beautiful renovation, so you should definitely check it out! And she also just released a quilt pattern for Starry Night, pictured above…visit her shop for more details!


I’m Ali from a²(w) and today I’m going to help you trouble-shoot a couple basic stitches. Nothing stinks more than trying to sew something and having your stitches look like the sewing machine barfed them out. Yes, this used to happen to me a lot until I figured out what was wrong.

Whether your sewing machine is new or old, this should help you get started. I always suggest looking at the manual, since the manufacturer knows best! While there are LOTS of fancy stitches out there and special sewing machines, we are going to focus on the basics.
Straight Stitch
No matter what kind of sewing machine you own, it will sew a straight stitch (well, as long as you feed in the fabric straight). This stitch does it all, from quilts to clothing to stuffed toys. The only change you can make to the straight stitch is the stitch length. In the image below, I have started off with a setting of 1 on the left. This means that each stitch should be 1mm long.  Can you see the individual stitches?? They are teeny tiny. Each line increases the stitch length by 0.5, up to a stitch length of 5 on the far right.
Stitch examples
Most sewing is done in the 2.0 to 2.5 range. If you are foundation paper piecing, you may want to decrease your stitch length so that the paper tears away easier. Top stitching and quilting are usually done in the 3.0 to 3.5 range. Basting and gathering stitches are the longest, from 4.0 – 5.0. Play with your stitch length and see what settings you prefer, then write it down!
Zig Zag
The next basic stitch is the zig zag stitch. I admit that this guy is my FAVORITE and I used it as a decorative stitch all the time! The zig zag has 2 options: stitch length and stitch width. Just like with the straight stitch, the stitch length is going to determine how far apart the stitches are.
Stitch examples-3

On the left you can see that I set my length to 0.3. The stitches are almost on top of each other. This is called a satin stitch and is used in applique. Right below that line the stitch length is 0.5, so just slightly further apart. Moving to the right, you see a stitch length of 1. I increased my stitch length by 0.5 per row (I didn’t change the stitch width) up to that huge 5 on the right. When finishing the seams on clothing, I usually use a 2.5 stitch length instead of a serger.

Stitch examples-2
Here I’m changing the stitch width. The stitch width is how wide your zig zag will be. Again, starting small on the left with a 0.5, you can see that this creates a very narrow line, barely noticeable as a zig zag stitch . Moving across to the right I increased my stitch width by 0.5 and left the stitch length the same.
Play with all the combinations to find what works best for your project. I frequently top stitch with a zig zag and bind my quilts with it. I also use it to sew labels into my items. It’s much more forgiving that a straight stitch because the width of it catches more fabric and it’s harder to tell if the line isn’t perfectly straight.
No matter what stitch you are sewing, it will look terrible if the tension if off. Some of the newer fancier machines automatically regulate tension, otherwise there is a knob or button. The best description I ever saw was that tension is like a tug of war between the top and bobbin threads. When they both pull with the same force you get a nice stitch and their numbers average out.
Here you can see the bobbin thread sticking up onto the top. This means that the top is pulling too hard! Ease up guys, turn the knob to a lower number. Or sometimes the top gets lazy and the bobbin thread pulls it through. See the top thread showing through to the back? You need to kick the top thread into gear and raise the tension (higher number).
Most sewing machines will have the standard tension marked with a dot or line. My machine averages out at 4, and I usually don’t have to adjust it too much from there.
Boo boos
Skipped stitches are the worst. Below you can see an example of what skipped stitches look like in both straight and zig zag stitches.
Stitch examples-4
What causes these is that the needle is struggling to get through the fabric and doesn’t make all the way down to the bobbin. If you’re having this problem, CHANGE THE NEEDLE. It’s that simple. Your needle is either too dull (time for a new one), or not large enough to accommodate the thickness of fabric.
Needles come in different sizes for a reason. While your small needle is great for sewing together thin cotton, once you start working with thicker materials or lots of layers, you need to get out a larger needle.
Mis-threading the machine is also a problem that causes ugly stitches but is a simple fix. If you’ve played with the tension and still can’t get the stitches right, take out both the top and bobbin threads and start fresh.Your sewing machine should have little arrows that will point you in the right direction!
Lastly, Give your sewing machine a good cleaning!! You’d be amazed at how quickly it gets dusty under the bobbin. Read your sewing machine manual for full directions. There are usually only a could screws that you need to remove though. I use a q-tip to swab out the nooks and crannies. Canned air is a bad idea because it just blows the dust further in.
I hope this helped get you on your way!!
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39 replies on “Sewing Back-to-School: Stitches & Tension

  • ChrissyG

    Great post! Thanks so much!
    I am very new to sewing and seem to be having a stitch issue. Every tutorial I’ve seen for how to make a skirt shows sewing the waistband and hem inside out, but the stitching looks better on the inside hidden part if I do that. Does that make sense? Any thoughts on why this would be or what I should do about it?
    I’m using an old Singer machine (Singer 247).

  • Anonymous

    Very Helpful … you clearly identified my issue as tension … and I was adjusting my tensioner (‘wheel’ up top) – but to no avail. I took apart my whole machine to clean it (it wasn’t that bad, surprisingly). Still very loopy bottom stitch. After a little more research though … I found my problem. You should mention here as well about the tension adjuster screw on the bobbin case, down below. Others may not know about this very important screw, and a very simple fix!

  • Anonymous

    I’ve been working with an old machine that was not used for several years and it had a rough time getting going. We had issue after issue the entire evening and then finally someone mentioned oiling it – plus we cleaned it out really well and it started to work pretty good – the issues always involved the threading – once even the tiniest bit of thread in the bobbin case slowed everything down. It’s kinda fun getting to the bottom of a problem (unless you are in a hurry)Thanks for your helpful info

  • patty cole

    My hubby and I have a sewing machine repair service. The main thing most people don’t do correctly is RAISE THE PRESSER FOOT when threading the machine especially through the tension discs. Also, cleaning between these discs helps to keep proper tension on the thread. With the presser foot up slide some stiff fabric back and forth between them.

  • CJ Latour

    Hey there Sara, just looking at your past posts. This one caught my eye because I’ve actually been wondering about the bobbin stitching. What exactly is the stitching on the back supposed to look like? I know what the front is to look like, but not entirely sure if what I have on the back is accurately the way it’s supposed to look like.

    Thanks for this post! I am actually thinking about making a small quilt sandwich with all the different stitches and making them bigger in each row.

  • KatrinkaJane

    Hi, Sara! I’m going crazy. 🙂
    My stitches used to be fine, but the last couple of times I’ve sewed, the underside looks great but the top is a straight line held down with little bumps from underneath. I know that means tension, but it looks the same no matter which setting I use, from 0 to 9 (only difference is how loose the underside stitches become)! What am I missing?

  • Helen H.

    Love your tension diagram! I am looking for some help with zig zag tension. The tension looks balanced on my straight stitches, but when I change to zig zag, I am having a hard time. I either see some of the top thread off center on the underside, or my zig zags begin to pucker. Is this normal? I am adjusting in .5 increments, and there doesn’t seem to be a sweet spot for the zig zag to look perfect underneath.

  • Dibba May

    I am so discouraged with quilting. I can’t seem to get the tension adjusted. I want to cry!!!! Thanks for the hints. I will get back to the machine and try again.

  • Sue

    My machine acts as it should with no cotton (good quality) threaded. but thread it up and the needle jams off to the side as though it is trying to zigzag. I have been messing with it all day and now am out of ideas.

  • Laura

    I am sewing together very thick layers in a zig zag stitch and the stitches are only skipping on the left side of the zig zag. When I switch to a thinner fabric the stitch works fine. I don’t understand why the thread is picking up on the right and not the left. Any ideas?

  • Abby

    Thank you so much for this!!!! I’ve spent the past 4 hours dealing with my thread breaking while doing a satin stitch for appliqué. I’ve read the manual, various books, and visited various websites. Your explanation is THE BEST and the easiest to comprehend. The tension diagram is awesome!!

  • Anne

    Oh, the pure awesomness of that tension diagram ! I used to always be so confused ! This made my day, thank you so much !

  • Candice Hargrave

    Ok so my problem is a little different… machine messes up the stitches. I wish I can attach a pic, anyways the stitch turn out looking well.. unfinished I guess. The string won’t get pushed through it just is a straight line with string come out from the back and loop over it and go back in. If that makes any sense o.0 it wont pull the string in the fabric so it doesn’t look like it loops in and out. I need help and fast! Thanks ~Candice

  • Leo G.

    Great post, Sara! This was really helpful for me in *understanding* my thread tension problem and I’m the kind of person who can’t solve a problem I can’t visualize by just following instructions in the manual. 🙂

  • Christy

    No matter which way I move the tension, the bottom thread always comes up the top and my top thread is just a straight line. What am I doing wrong?

    • Tanya

      Mine is doing the same thing , it seems to have a straight line and lose. After I’m done i can just pull the straight line of thread out eith no problem. The other thread is just looped over it and not even tight. Like i said i can pull the other piece of thread the one that looks like a line right out. Please any help will be much appreciated.

  • Dawn

    The image you used is from my book The Pocket Tutor an Essential guide to Patchwork & Quilting by Dawn Cameron-Dick which was provided for me by Bob Persel from Superior Threads.
    One ought to give credit when using other people’s work.

  • Edith Glushek

    I am having trouble with the last stitch I used showing up in the next stitch. zig zag reverting to decorative for one or two stitches then back to zig zag any ideas why.

  • Jennifer Hebel

    This was SO helpful and informative. I’m probably at an intermediate skill level, and almost everything you said was useful and new info for me (I’m the “slap a few layers of fabric together and wing it” kind of sewist so I never had any formal teaching) thank you!


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