I am getting erratic behavior when I adjust the upper thread tension knob on my sewing machine. For example, no matter how slowly I adjust it, it's either too loose or too tight. Or during sewing the tension would suddenly change from slightly loose to way too high despite me not touching the knob.

I am wondering if it happens because I don't oil the tension discs. If I am supposed to, doesn't that mean that the thread will become greasy during sewing? And won't thread just immediately wipe the oil off of discs?

I couldn't find an answer to my question on the Internet. Everyone just says that the machine needs to be oiled, but nobody says if the thread tension discs should be oiled too.

My sewing machine is pretty old. I have lost the instruction manual, and I couldn't find a copy on the Internet.

  • 2
    Even if you don't have the manual, the make and model may still be helpful, especially as some machines need oiling in more places than others
    – Chris H
    Oct 6, 2021 at 10:13
  • 2
    Make and model is definitely helpful; some machines don't actually require oiling at all, just professional maintenance, others have different locations where the oil should be added. And it's possible to find just about everything--I've even found the manual for my >100 year old machine. :)
    – Allison C
    Oct 6, 2021 at 13:55
  • It is sometimes helpful to put a strip of paper or newspaper between your fabric and the thing that grabs the cloth to move it along. / Make sure you don't have any mistakes in the rest of the upper threading sequence, as this kind of mistake can really mess things up. / Make sure your needle is a good size for the fabric and is properly seated. / Clean the bobbin case (Q-tip, brush) and make sure you're not threading it backwards. Also make sure the thread unspools easily from the bobbin, ... Dec 7, 2021 at 8:31
  • ... and make sure you're using the right size bobbin. / Ordinarily we're not supposed to adjust the bobbin tension, but if all else fails you could try a miniscule adjustment to see if that helps. Dec 7, 2021 at 8:32

1 Answer 1


Nope. You do not oil the tension discs. You may need to open it to remove lint or check for damage, rust, and wear. Then, it may be that you need new discs. But they are not part of the lubricating maintenance. Singer CG 550 tension I agree with @allison c to have it looked at by a professional on occasion.

Need to add this information: upper thread tension: “If the upper tension device appears not to be applying pressure on the thread when set on the half-way position, check that no lint or thread ends are lodged between the discs. Raise the presser foot (this will open the discs) and blow between the discs (or use a long-haired brush). This will remove any lint or thread ends which may be fouling the discs. It is not realized by many sewing machine users that raising the presser foot also releases pressure on the tension discs allowing easier removal of work. This is in fact the case with all but a few very early machines. It is, therefore, very important always to thread the upper thread with the presser foot raised in order to allow the upper thread to negotiate its entry correctly into the discs.”

bibliography & research

(1) Lucking, Peter; The Sewing Machine Handbook, Arco Publishing, Nee York 1985.

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