Understanding Differential Feed (For Sergers)

understanding differential feed
I have never really used a serger until recently…I didn’t think I would actually use one very much (even if I could figure out how to use it).
But boy was I wrong!
I LOVE my serger and use it ALL THE TIME.
But before I started using it I wanted to understand how it worked…I am still learning a lot about my machine but one of the most important things I’ve learned so far is about differential feed.
Now, don’t quit reading and pass by this post just because it sounds like it’s going to be technical!  Understanding what differential feed is and how to work with it can make all the difference between having your project look “homemade” and having your project look “handmade”.
I promise, I’ll make this lesson brief…just the facts (and a few tips)…and I swear it can change your world.  (Your sewing world anyways…I swear it changed mine!)
Now, let’s get started.
differential feed 1
*What is Differential Feed?
Simply put your serger has two set of feed dogs.  The feed dogs sit underneath your presser foot and are what move your fabric through the machine…AND it’s the differential feed that controls the movement of both of these sets of feed dogs.
*Wait!  The Feed Dogs Can Move at Different Speeds?
Yes!  If your differential speed is set on “N” then both of your feed dogs will be moving your fabric through at the same speed.  (I think of “N” as “Normal”.)  However, if you move the lever up to 1.5 the front feed dogs are going to be going faster than your back feed dogs which will cause the fabric to gather.  Or….if you move your lever down to 0.7 the front feed dogs will move slower than your back feed dogs and cause your fabric to stretch as it moves through the machine.
*Where is the Differential Feed Control and what does it look like?
You can find the differential feed lever on the right hand side of your machine and it will look  like this:
 differential feed 3
(Or….it can be a round shaped dial that will be sticking out of the right hand side of your machine.  In that case the numbers will be written on the dial itself and not on the machine.)
*So exactly why would I want to turn my differential feed up?
One reason you would want to turn up your differential feed is if you are using a fabric that stretches or puckers.  With the front feed dog taking the fabric in a little faster than it is exiting it helps to prevent your knits from stretching and becoming wavy.  Another reason you may want to turn up your differential feed dial is so that you can intentionally gather your fabric.  (Note:  To do this you will turn your dial up a lot farther than just to keep your knits from stretching.)
*And why exactly would I want to turn my differential feed down?

Light weight fabric tends to slip and pull and pucker.  However, if you turn the dial down and the back feed dogs are pulling faster than the front feed dogs that will help to keep your fabric taut as it moves underneath the needle and will prevent any unwanted puckers.

*Is there anything else I should know?

Yes.  But this is enough information to get you started.  And just remember:  You will need a little practice.  Everyone does.  But with that practice will come an understanding of how the fabric is moved through your machine and then you will be able to master any type of material you want to work with and have your project turn out fabulous!  You can do it!

differential feed 4


Hopefully that was informative and not to painful!

Just understanding what differential feed is and how to control it has already made a huge difference in the quality of my serged garments.  (And has lessened my anxiety about serging…everything in sight….)


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  1. says

    I’m thinking about a asking for a serger for my birthday. So it’s really good to gather some information about it beforehand. Thanks a lot!

  2. says

    Wow. That’s awesome. No-one ever explained it to me like that before and now it makes SO MUCH SENSE. YAY! My overlocking is going to be WAY better from now on.

  3. Mary says

    Thank you so much! I’ve been trying to figure out why my knits stretch when many bloggers post serging is so easy with knits. I just looked in my manual and sure enough it said to change the differential feed to 1.5 – but now I understand why. Great – I just added 3 knit projects to my to do list!

  4. Shae' says

    I got a serger this past Christmas…and I’ve only tried it once. It scares the heck out of me! I would love to learn more about it…thinking of taking a craftsy class to get more comfortable with using it. When I opened it I was so excited and thought I would jump right in…well going thru the instruction book put the brakes on that! Thanks for the info. Maybe now I will summon some courage and attack learning more about it again.

  5. Kerrie says

    Dh surprised me with a BL serger two Christmases ago and I LOVE it.
    I use it to gather a lot and love it but didn’t know the mechanics behind it!
    Thank you!

  6. Linda Lutich says

    Thank you for that great explanation. I always wondered why my napkins would be stretched out on the crosswise grain when I did a rolled hem. Now I know that I need to change the differential for the crosswise hem!!! Live and learn.

  7. Jessica says

    This is super helpful! Thank you! My wonderful husband bought me a serger for Christmas and I LOVE it, but I had no idea of what the differential feeds did. This will make sewing easier 🙂

  8. Phil says

    I was told by a sewing instructor to increase the diff. feed to about 2.5 to sewing a sweat shirt but found that the entire thing produced lettuce edge and I had to redo everything. I decreased the diff. feed down to .5 and go beautiful edging. Still something to learn.


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