When it comes to bobbins and thread I'm definitely a waster. Touch & Sews use a special 2 pc. plastic bobbin. They also seem especially finicky about the bobbins you put in them. If the tolerances are off even a little the machine WILL jam. The 648 I bought had a full broken bobbin in it. I think the thread swelled up from moisture in the air and eventually was more than the bobbin could handle. I also toss suspect bobbins. Life is too short to waste time on a distorted bobbin and the frustration that comes with one.
Rodney