I have a Singer 348 machine. The sewing on the top of the fabric is fine but the underside has lots of large loops and the thread is tight when you pull it. I have changed needles, used empty bobbin, tightened bobbin screw and checked and rechecked threading instructions but no use.
My husband removed the bobbin case and cleaned it.
Can you please help.

anne sl, July 2009

Hello Ann,
The 348 was one of my favourite machines, make sure first of all that the machine is threaded properly with the presser foot up, make sure the needle is in the correct way round, remember that these models are very fussy on the type of thread, use 40 or 50 sylko or Guttermans if you can, top tension should be about 4 or 5, you should only just be able to pull the bottom thread through with slight resistence, if it is too tight slacken the screw on the bobbin case about a quarter of a turn anti clockwise at a time and test.
ken

drivewithken, July 2009