I was sewing my teapots out and on one machine I started noticing

bobbin thread coming up in the satin stitch...I removed my thread,
cleaned the bobbin, re-threaded....it was still happening....I
repeated the process again and still my bobbin was coomming to the
top. I noticed that when I pulled the bobbin thread it did not pull
evenly and smoothly. I have a box of pre wound bobbin in plastic
casing. I took out the bobbin and there was a burr on the side that
kept catching on the case just enough to mess up the stitching. I took
a nail file and filed it down, replaced it in the case and the
stitching was good again. So if you get this problem, check your
bobbin...it may be hanging up just a tad....
Elizabethj,