shnnn

66 bobbins are dished a little and are slightly shorter than 15 bobbins if I'm remembering right - I'm not home either
What makes me think it's a too much tension issue is that it's pulling a pucker. If it was too loose it would leave a loop. And since it's the bottom that is smaller - it seems like it the bobbin pulling. But my logic maybe flawed, it has happened before!

coachmatthewsvhs

This is how the thread looks on the top side of the material: the thread runs long with a tiny stitch ... then a longer stitch again. I've found how to follow this post. I am using much thinner fabric than my last project. How do I tighten my presser foot tension? Is that the thumb screw on top of the machine...... is right tighter and left looser?

coachmatthewsvhs

what is the tension spring? (terminology I don't know)

miriam

The tension spring is a little wire the thread hooks in as it passes through the tension then on to the take up lever. It travels just a bit as the thread is pulled through by the needle. I had a Spartan that had a messed up tension spring. I had to unscrew the tension at the side of the machine and do some adjusting to get it to hold in place. I found that info on the sewing machine repair website listed in the link I posted earlier for tension problems.

Charlee

Heather, check this website, it shows the tension assembly of the 66. The tension spring is "F"

http://www.ismacs.net/singer_sewing_...g-machine.html

miriam

it is also "n"

coachmatthewsvhs

Working again today... had a sleepover with my grand daughter last night. I have checked the tension site and will check my spring when I get home. My bobbin has a slight curve to it... I also have one that has a lot of curve.... will also try to blow out the bobbin case. Thanks everyone!

shnnn

my class 15 bobbins are totally flat-- no dish what-so-ever.... and a good cleaning never hurts. The presser foot tension is straight above the foot, and as far as I remember it is righty tight lefty loosey.... (and if that doesn't work there's only one more option )

miriam

http://www.tfsr.org/pub/technical_in...echanism_2.pdf
maybe this would be of help - I've had more than one tension I had to totally take out and then re-install - it worked after that - this site was very helpful to me - the way I figure it - if you can read a pattern to sew something you can read the directions to fix a machine

Morag

If it is a full sized machine it is most likely a 66. The 99's are 3/4 machines and do not fit into a regular sized cabinet.