Thread bunching (also known as birdnesting or thread looping) is one of the most annoying sewing machine problems because it is tedious to unpick and tends to happen at the most inconvenient times. If you’re trying to figure out why your sewing machine thread is bunching up under your fabric, consider the following problems.
- Your Feed Dogs Are Down: If your fabric is not feeding through your machine, you will get bunched up thread under your fabric. There is a lever on your sewing machine to disengage the feed dogs for quilting and free sewing, so make sure that your feed dogs are up if you have lowered them recently for other purposes.
- Your Bobbin Is Put in Backwards: Every sewing machine’s bobbin case is a little different — some need to have the bobbin inserted clockwise and others need the bobbin inserted counterclockwise. If you are getting thread bunching, check to make sure your bobbin is inserted correctly in your sewing machine. There’s usually a diagram right on your machine, but if not you can look in your sewing machine manual.
- Your Thread Tails Are too Short: If the thread tails coming out of your bobbin and needle are less than two inches long, they may get pulled into your sewing machine when you begin to sew, causing thread bunching. To avoid this problem, you can either hold the thread ends until you have sewn a couple of stitches or always make sure that your thread tails are at least three inches long before you begin sewing.
- Your Upper Thread Is Not Threaded Correctly: When there is thread bunching on the under side of your fabric, it could mean your upper thread is not threaded correctly. Rethread your sewing machine to see if it solves your problem. Make sure that your thread goes through the loop that goes up and down as you sew.
- Your Sewing Machine Tension Is Off: Your upper thread tension may be too loose if you are getting thread bunching under your fabric. Try tightening the upper tension to solve the problem. Only move your tension a little at a time.
- Your Presser Foot Is Not Down: If you forget to put your presser foot down, your fabric will not feed through your machine as quickly as it is supposed to and cause thread looping or bunching under your fabric. Make sure to always put your presser foot down to avoid this problem.
- You’re Not Using a Spool Cap: Spool caps keep your spool of thread from getting out of control. If you don’t use one, you make be letting the spool spin too quickly. So, always use a spool cap, especially if you have a horizontal spool pin to avoid bunching or looping thread.
Visit our article on Sewing Machine Troubleshooting for more information.