On the top I see the loop from the bottom which should be between layers of fabric.. i have done lots of test runs, changed thread, bobbins, adjusted tension probably 50-75 times. Also I tightened screw on bobbon case about 1/4 turn. i am using cotton fabrics and warm & natural fabric. Help Please!!
Caroline, in my experience when you can't adjust the tension it is usually the hook timing as you suggest. Before this, do what Rodney suggests and check bottom tension: It does sound as though the bobbin has none (the loop happens at the side opposite the weak thread) and checking this is way easier than checking the hook timing (which isn't hard either, but path of least resistance). Check by pulling both threads in turn with presser foot down and the
bottom thread should always have lower tension than the top (advice was from Peter Jackson from Jacksons Sewing in Melbourne, so I took it as gospel
).
As per Rodney's reply, there might be thread, rust or dirt fouling the thread path on either top or bobbin and pulling thread along the path should reveal this.
If your top tension is set correctly, with presser foot down pull lightly at the top thread as you twist the tension dial anticlockwise. As the numbers approach zero the thread will move. At zero there should be almost no resistance at all.
tfsr.org is the site Rodney referred to.
http://www.tfsr.org/publications/tec...achine_manual/ for the manual. I agree that this is an excellent manual.
There are some machines where the timing occasionally goes out. 201s aren't one (I've never seen it in the 30 or so 201s I've had), but 319s are (not sure why). Maybe 328s are too, in which case you should familiarise yourself with the timing procedure. It isn't hard, and you'll know straight away next time your tensions are out. I've never had a 328 either but I had a 327 (identical except for the cams) and had to set the timing on it.
They do indeed use class 66 bobbins. Hope you're using metal ones.