Bernina question?
 

When I purchased my Bernina (new) many years ago, it would sew through 5 layers of denim. Today I tried to sew through 4 layers of cotton fabric and it would not go. The machine bogged down and the bobbin thread knotted badly. I have noticed it seems to be getting weaker. I have a Superior Needle in it and the thread is new on a cone.

Any ideas what the problem is or what I can do to fix it?
I also tried to sew a new zipper onto a fleece jacket and what a mess that was.

Thanks for your ideas and help. :sew:

If you haven't had it serviced in a while, maybe it's time. When you say many years, how many? All things wear out.

It helps if you post the model number. Mine is a 1530 is still running smoothly but I am overdue for getting it serviced. It is just like a car you have to have it service every 12 to 18 months. What type of thread does your manual suggest you use?? I was told to use Mettler Silk Wrapped thread.

I assume you have cleaned and oiled it if that is directed in your machine manual.

The needle may also have something to do with it. Is it dull? What size? I discovered I had to go up to a size 16 needle when I was sewing 4 layers of a denim tote.

I agree to check the size of the needle. Re thread. Put bobbin in again. Check that you have the correct presser foot on. Adjust tension and practice on a sample. My Berrnina is very finicky too. Also, Bernina has a height adjustment too that came with my machine and is helpful. Also, check in the bobbin area for a scrap of thread or excess lint. Good luck.