All sewing machines have a few essential parts that regulate various functions that allow the machine to work correctly. Tension disks, which aid in thread control, are one such part found on many machines like the Juki F300. To ensure Juki sewing machines operate properly, it is important that you understand what tension disks do, where they are located on the machine, and how you can adjust them for best sewing results.
What Is The Role Of Tension Disks?
Tension disks control thread tension as it moves from the spool to the needle to make a proper stitch. Without the right tension, stitches may either be too loose or too tight. The disks are where you can make an adjustment to correct improper tension. On older models, you may find manually adjustable disks located on the outside of the machine. Tension disks may also reside inside newer models like the Juki F300 that are controlled electronically.
Symptoms of Thread Tension Problems
Properly tensioned sewing machines produce snug and even stitches that look uniform on both sides of the fabric, smoothly joining it together. This means the top and bobbin thread lay evenly on the front and back of the fabric, with the intersecting loop hidden between the two layers. Machines that require tension disk adjustment may exhibit one of the following stitch symptoms:
- Tension Too Loose - If the top thread is pulled below the fabric surface and lays on the back of the fabric or the bobbin thread is pulled tight, the top thread tension is too loose. It must be tightened using the tension disks so that the top thread is snug enough to properly loop with the bobbin thread.
- Tension Too Tight - If the bobbin thread is pulled through to the top of the fabric and the top thread is pulled tight, the top thread tension is too tight. It must be loosened with the tension disks so the top thread is more relaxed and no longer pulls the bobbin thread through.
Adjusting the Tension Disks
Fortunately, adjusting thread tension on Juki and other sewing machines is simple to do by using the tension disks. On manual models, simply nudge the tension knob to the left to loosen the top thread or to the right to tighten it. Electronic models can be adjusted on the control panel, which either loosens or tightens the disks as required.
Make slow, incremental adjustments and test the tension. Work until the machine forms correct stitches, with the top and bobbin threads snug and even.
Keep the Tension Disks Clean
Tension disks on sewing machines can collect lint and pieces of thread which can interfere with thread tension. To keep them clean, brush them frequently. Always check for loose threads so that if it becomes necessary to adjust the disks, the adjustments will be accurate.
There are many reasons why any machine, including Juki sewing machines, may produce loose or uneven stitches, from thread and needle problems to a poorly functioning bobbin. If other concerns have been addressed and stitch tension is still off, tension discs may need to adjusted. Whether you do this manually or use the electronic controls if you own computerized models like the Juki F300, the tension disks make proper control of the tension of both the upper and lower threads possible!