What a difference thread makes!

I just about have my fleet of machines up and running.  Part of the testing is to sew all of the available stitches in different widths and lengths to see how they work.  Last night I was using the Singer 503 and doing a zigzag stitch.  Man was I having issues with the tension.  Even with it cranked all the way up to 9, I was still getting top thread on the bottom of the fabric.  When I had it at a more normal 3 or 4, well, it was just a disaster!  And the needle thread kept breaking on me.  I switched needles, but that didn’t make a difference.  I tried re-threading both the needle and bobbin thread . . . nothing.   I loosened up the bobbin tension and that was too loose, and tightening it didn’t work either.  So I figured I needed to adjust the tension setting, which meant partly taking apart the tension mechanism.  I got it to where I liked it, but when I put the number dial back on, I couldn’t even get past number 4!  Clearly, not a good situation.  What to do?  What to do?

I figured changing the thread might help.  (I’d already done this before, but I decided to try a spool that seemed a bit newer.  (If you’ll recall, I got a TON of free thread a few weeks back, and much of it was somewhat oldish.  I’m guessing that the fibers have worn out a bit over time!)  I also switched to a different thread in the bobbin.  Got the tension worked out and was able to turn the dial the full range, from 0-9!  Yipee!  I went ahead and sewed the one thing I was wanting to sew (gotta strike while the iron is hot, ya know?!)  Then I went back to the original thread  . . . . . you guessed it, the tension was a disaster again.  So clearly, the thread made a huge difference!  I’m still really happy about my free thread, I’ll just have to be careful what I use!