Thread catches
 

I have a singer 401A, 431G, and a 503. I can sometimes sew for quite a while with them and sometimes for only an inch or less and then the top thread seems to “ catch” and bind up, making a knot. I have to stop, pull it out, and start sewing again. This happens with all of these machines. Does anyone have an idea of what might be causing this? DH and I are just getting started on working on our machines. We have done the oiling and have taken the bobbin case out to clean and make sure there are no leftover threads. We don’t know what to try next. Thanks in advance for any help.

I don't know what it could be. I have a 301a and a 503 and have never had this problem with either machine. Don't forget to take the top off and oil and clean in that area as well we underneath.

Have the same problem with my Singer 403. Cannot seem to find the problem. I have cleaned, taken apart the tension and reassembled it, cleaned the bobbin area thoroughly, nothing corrects it. Most aggravating!

I'm not sure what you mean by making a knot. I had a problem with my 401 that would get tangled up and lock up the machine. I must have lost the photos when my computer crashed. What seemed to happen is that the top thread would (showing on the bottom) get longer and longer until it finally got stuck in the bobbin area and locked up the machine. You had to cut out the "knot" to free the fabric. By cutting it out, you couldn't determine what it was catching on.

This was my solution: https://www.quiltingboard.com/vintag...t-t299108.html. It didn't totally solve the problem, but helped considerably. I would guess that it reduced the instances by 95%. Here's the youtube video: https://www.youtube.com/watch?v=j5Y3UTg2Yj8 .

(Note here that my problem looked like increasingly longer loops on the bottom (which you can't see while it's happening.) until it locked up the machine by getting wrapped around something. This happened in the middle of a seam, not at the beginning. It may or may not be relevant to your problem. However, it's not difficult or expensive to try.)

bkay

Hi there; I actually had the same problem with my power machine. In my case, it turned out that my needle's eye was too small for the thread I was using. If you determine this is not your problem
after trying a larger size needle; then it could be your upper tension is too tight... not allowing the thread to come back up with the moving thread guide. (why can't I get the term.. the bobbing up and down guide) If that doesn't work, then check your bobbin tension . if that is tight, then issues will arise.
Since you say it happens on all your machines, my first suggestion is probably the reason.
In my situation; I was sewing a heavy nylon thread with too small of needle eye, preventing the thread from freely flowing thru. Once I went up to a larger needle, all was well!
Antique or modern, some issues are common.
Hope this helps!

Are you using the same thread in all the machines? If that is the common factor perhaps that is the problem.

Quick update. Yesterday I recleaned the bobbin assembly on the 503. It wasn’t very dirty. So I changed thread (back to a 50 weight) and did a sampler with all 22 cams. Not one catch/break. I have been using an 80/12 needle but had changed to a 40 weight thread when the problems occurred. I had no trouble with this combination on my 201 machine. I love that machine! But sometimes I need more than a straight stitch. So the problem seems to be the thread/needle combo.
Thank you all for your input.

I'm so glad you were able to work out this problem!
I think you should try to stick with the #50 thread, unless you are sewing lightweight fabric. I even will stitch with a #40 thread in the bobbin just because it lasts longer between rewinds.
That may help you get more out of the 50 weight. You should not see any visible difference if your bobbin tension is not too tight.

glad you found a solution for that machine.
What my mind wondered since you said it was across all your machines is if you are threading with the foot down. That can cause problems...

I do often thread the needle with the foot down as it seems in the way. Why would this cause problems? I’m just trying to understand all that I can.