sewing machine adjustment question

Are you using a welt foot when you do this? If not the welt may be raising the feet to high and disengaging the tension.

Loops on the bottom: top tension is too loose or you threaded with the presser foot down so the tension disks didn't open to receive the thread. Or tension has something stuck in it and needs cleaning. OR thread is way too heavy for the size of needle you're using.

Loops on the top: Bobbin tension too loose or bobbin tension needs cleaning

Snarls at beginning of seam: you forgot to hold the threads behind the presser foot while starting.

Thanks for all the good replies. I will check my upper tension. I know I am keeping it REALLY loose because otherwise, after about 10 or so stitches, the discs really, really binds. I will disassemble, clean and polish those little discs. This machine has not been used for over a year and was kept in a slightly damp environment.

Yes, I am using a welting foot and the presser foot is down.

Thanks, everybody!!!

BTW, not important, just curious. If I sew by manually turning the wheel, my little brain tells me that for every cycle of the needle, the hook down below should go around one full time. That being the case, why do I still get a jumble of thread underneath my seam? I guess it's tension, but from where does all that thread come? Confusing!!

Thanks,

Ivan Vegvary

One of the characteristics of vinyl coated fabric is that the stuff grabs and hold onto the thread, not allowing the take-up lever to take up the excess thread. The can create superb snargles on the underside... This is especially so if you use a heavier thread and an insufficiently large needle and/or one of the wrong type. I find I get better results if I use a longer stitch and a larger needle, such as a