Let's see, the VX560 once got a burr put into the shuttle hook that caused some problems until I took it apart and using a metal file removed the burr. I think that happened while I was stitching on some thin metal to make some decorative additions to an art quilt.
The PC420PRW somehow got a huge chunk taken out of the shuttle hook on the drop in bobbin case, but it kept on sewing just fine. I thought it didn't look right, but since it sewed fine I kept using it. My tech said she couldn't believe that it kept sewing like that. Not only did it keep sewing, but it sewed beautiful stitches including all the decorative stitches. I did replace that part, just in case. LOL
I've never had a finicky sewing machine, all 4 of mine seem to take pretty much whatever I throw at them...but then again, I've never used fray check in place of oil--
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