Thread Cutter Maintenance

June 21, 2011

Having a thread cutter on your APQS machine means not wildly stabbing under your precious quilt top with a scissors, trying to trim your bobbin thread. Good care and maintenance can keep the thread cutter slicing just as you expect; and when it needs a little adjustment to keep working at peak efficiency, that's easy, too!

Let's dispel a few myths about the thread cutter. First, the "arm" that you see capturing your bobbin thread and pulling it across the throat is NOT actually the thread cutter blade. While its leading edge is beveled, it is not sharp. It is beveled so that it can slip right between the two small, square pieces of metal you see underneath the clear Lexan cover. Look carefully at those two small square pieces and you'll see that they DO have a sharp edge on the right side. The puller arm grabs your bobbin thread and carries it over to the two thread cutter blades. The puller arm slips between the two sharp blades, which then slice your bobbin thread. Neat!

 We often get calls about a mysterious "notch" that appears in the thread cutter's puller arm. Quilters are convinced that they have somehow damaged that arm and put a nick into the arm. Here's the good news, that notch is supposed to be there, and you didn't do it, we did! That notch stops your bobbin thread from sliding too far down the puller arm as it travels toward the thread cutter blades. You can relax and not worry that you dinged your cutter arm.

Lint build up under or between the thread cutter blades (remember--those are the two little square metal pieces under the Lexan cover) will keep your cutter from slicing the thread. Use compressed air and direct the air flow into the circular cut-out in the Lexan cover, aiming it from the rear of the blades (near the brass screws) toward the front of the blades where the puller arm enters. If you blow air the other direction by aiming it into the blades themselves, you could force the lint and debris farther into the blades instead of forcing it out from between them. Clean your cutter blade area often.

With lots of use, your thread cutter blades may need some slight adjustment or eventually may need replacement. Look at the two small, brass-colored screws you see inside the circular opening of the thread cutter's Lexan cover. These screws adjust how tightly the blades pinch together when the puller arm comes across to meet them. If the blades are pinched too tightly, the puller arm can't get between them to slice the thread. But if they are too far apart, they can't slice the thread either.

Tiny "wave washers" are sandwiched between the blades at the rear, and the little brass screws hold them in place between the two cutter blades. When stacked together these little wave washers almost look like lasagna noodles, with ridges on the edges. They act a little "springy" when they get pinched together. So, if the thread cutter blades' sharp edges are not slicing the thread, those brass screws may need to be tightened slightly to compress the washers just a bit. Adjust each screw the same amount and only a little at a time. Test the cutter again.

Over time, the thread cutter blades can become dull and the wave washers can lose their "spring". If these adjustments do not give you good results, it may be time to replace the blades and washers. We have more detailed instructions available to help you trouble shoot a thread cutter that is not functioning the way it should. Be sure to call us and talk with us about the trouble...we'll work together to get you slicing again!

 APQS Customer Support Line:  800.426.7233