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zipper foot throws off tension?

AltonPM | Posted in General Discussion on

I have a Pfaff Hobby 4240 and am sewing a poly coil zipper into the end of a lightweight flannel bolster cover.  When I baste one side of the zipper onto the seam allowance with the regular foot, the stitch looks fine.  When I try this with the zipper foot – so that I can get closer to the zipper – the bottom of the stitch gets very loose and sloppy and pulls out. 

This also happens when I try to use the zipper foot for the final step of topstitching in the zipper (also, the foot causes the lighter top fabric to wrinkle badly).  These both occur whether or not I’m using an interfacing.

When I try to adjust either the bobbin or the top tension for the zipper foot, I can’t come up with anything that works.  I don’t normally touch the bobbin tension, by the way – and I can sew successfully with the normal foot on many weights of fabric.

Any ideas?  Is there a different foot I should be purchasing, or technique I could try?

Thanks in advance!


  1. SewTruTerry | | #1

    It may not have anything to do with the zipper foot.  When you put the zipper foot on do you unthread the machine or anything differently than normal?  Usually when there is a mess of thread underneath you must first look at the top thread.  I know this sounds backwards but it works everytime.  Simply take the top thread out and rethread it being careful to have the pressure foot up and the needle in the most upright position possible and rethread based on your machines guidelines.  Another possible is that with the zipper foot on you are not able to lower the pressure foot all of the way and not fully engaging the tension on the machine try giving it another little pat with the hand to make sure that it is fully down. 

    Let me know if this doesn't help there are a couple of other things that I would try but a little lengthy if you don't need it.

    1. AltonPM | | #2

      Terry, thanks so much for the reply.  I have actually run a few tests by just trading out one foot for another (with the thread in place) and sewing through the exact same fabrics.  The thread isn't really getting bound up underneath in this case, but the bottom of the stitch is really loose - barely catching the loops from the top thread.  The stitch just pulls right out if I pull on the bottom of the stitch, even if it's a fairly small stitch.

      I would love to hear your other ideas ... and I'll try to take a digital pic of what's going on and post it online tomorrow (if I don't have a baby first - I'm 8 days overdue).

      On another note, I wish I had had your advice about thread-binding a few weeks ago!  I am new to this, but I realized recently by trial and error that rethreading the top thread and/or changing the needle usually takes care of it, when it occurs.  That, and the bobbin thread can't be too tight - when I get it working I try not to mess with it too much.  It's really nice to hear reinforcement that what I think solves that problem may be the correct approach ;-)


      1. SewTruTerry | | #3

        I remember when I went to buy my first new sewing machine when I was 1 week shy of my due date with my son and could not get my sewing machine to work no matter what.  My son was delivered a week after my due date and I thought my dsh was going to be the one to have a cow instead of me.  LOL  I mean I gave birth to a         9 lb 4 oz bouncing baby boy and I am under 5 feet tall.  LOL 

        Something else that I can suggest or ask really (I know that it might sound really dumb) but are you using the manufactures recommended needle.  I know that Singer machines will only take Singer needles (learned the hard way after 3 trips into the dealer/ repair shop).  Do Pfaffs require their own brand of needle?  This could cause skipped stitches. 

        Well take care and deliver that baby already.

      2. SisterT | | #4


        Do we have a baby report?

        Sr. Tracey

      3. betsy | | #5

        I also have a Pfaff, and with one zipper foot, I had to disengage the walking foot; this seriously threw off the tension and stitching. Are you using the walking foot (or differential feed, or whatever it's called these days)? Do you have another zipper foot that allows you to use you walking foot? Also, Schmetz needles are definitely worth purchasing.

        Twenty two years ago, my son was due on Sept. 26, but waited to arrive until my birthday, now our birthday. I'm at the computer to send greetings to him now. Birthday or not, he'd be happier to hear the phone ring after he wakes up.

        When is your birthday? (I hope it's not in May!) Good luck!


        1. AltonPM | | #6

          My birthday is in May, as a matter of fact :-)  Yesterday was my husband's birthday and I was hoping that the baby didn't choose that day.  I'm still here, no signs yet - I'll be induced at 42 weeks on Monday if nothing happens.  Tomorrow's the full moon, so I'm crossing my fingers!

          Okay, here's a silly question:  is the walking foot the same as the feed dog - the little bars on the metal bottom plate?  If not, then I don't have a walking foot.

          I talked to the local Pfaff repair guy yesterday and I think we might end up taking the machine to him after I have the baby and am not using it for a few weeks - he has a bunch of standard Pfaff feet he can try with it, but without looking at it, he can't think of any reason for these problems, either.

          I'll try to post pics online later - I think it might help!


          1. AltonPM | | #7

            Okay, they aren't great, but I've put pics of my zipper foot online:


            I actually scanned the stitches themselves and will post them to the same location -


          2. SewTruTerry | | #8


            The pics are pretty good and clear.  Now for a stupid question perhaps on my part but here goes.  When you are trying to sew that pesky zipper are you moving the needle position over? Because in the pics it looks like the needle is in center position.  If you don't move the needle over you will not have enough fabric under the feed dogs to put proper tension on the thread there by getting the mess on the bottom.

            By the way has that baby made his or her appearance yet?


          3. betsy | | #10

            Remember, "the only silly question is the one that isn't asked". There are so many questions to be asked in this forum because we are each working with different machines of different generations AND we are often trying to describe processes. That's not easy even for Click and Clack Car Talk callers, and they are able to vocalize sound effects! The walking foot is an additional presser foot that comes down behind the sewing machine needle, giving the fabric an extra little push to balance the feed dogs (the little siver ridged pieces on the machine bed) which are pushing fabric  through from the bottom. Whew! I welcome anyone else's explanation to clarify that one!

            must run, best wishes with the baby!


          4. AltonPM | | #11

            Thanks everyone!  I have to say that this is a really friendly forum.  As an old-home owner, renovator, and architecture enthusiast, I subscribe to ALL of Taunton's magazines and read all of the forums regularly ... but I no longer post questions on a few of the forums because they can be so unfriendly and impatient.  I have a master's degree in engineering, so my questions there aren't THAT uninformed.

            Since I've just recently gotten into sewing, I have found this forum to be GREAT!

            Anyway, I'll experiment with the tension settings today - I've played with them a bit, but will do so in more earnest based on your suggestions. 

            I'm a full two weeks overdue with the baby today, so they'll want to induce tomorrow - I'll come back when I'm lucid and let you all know what happened with the zipper foot!


          5. AltonPM | | #12

            I'm back ... with a 2-week-old baby boy named Perrin!  He was 9 lb, 9.2 oz and 21" long at birth.  I was in labor for 67 hours after being induced, so it was a long birth week at the hospital.  Needless to say, I'm not getting a lot of sleep these days.

            I did take the sewing machine into the repair shop this week and he took one look at my test runs with the zipper foot and said the timing was off and it needed a tune-up.  I'm getting it back today, hoping this did the trick!

            Thanks again to everyone!


          6. FitnessNut | | #13


          7. SewTruTerry | | #14

            Congratulations on the new baby.  At least now you have another one to sew for.

  2. becksnyc | | #9

    I agree with what Terry said in her last reply, that the crux of your problem lies in the fact that not enough of the foot is making contact with the feed dogs.  I work full time on a Juki, and when I change to my zipper foot, which is half the width of a straight stitch foot, I have to tighten my tension a full rotation. The lack of full contact between the foot and the feed dogs means the fabric/zipper don't get pulled along as far as with a normal foot, but the same amount of thread is feeding through.  The excess ends up as loops of the upper thread which slouch around on the underside of the fabric.  Don't be afraid to tighten your upper tension, but I wouldn't mess with the bobbin tension in this case.

    Hope all goes/went well with your new little babe!

    Becks NYC

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