I have had problems with thread breaking at the point when I was in the middle of my quilt. I finally figured out that it was the quilt sandwich getting trapped at the corner of my my Sew Steady table, with so much bulk right at that point when I leaned forward to FMQ I would trap it there with my elbow. It snapped the thread every time. I have trained myself to lift and bunch that area of the quilt every time I need to move my hands. You could check to see if this is happening to you. just a thought.

I use a 90/14 or 100/16 top stitch needle for FMQ, it seems to really help.
Sharon

I use Aurifil for all my piecing . . .it goes on my horizontal spool, but I have to switch the end cap to the opposite end so the thread comes off the spool front over to back instead of under to back (if that makes sense).

Sitting down to do some piecing this afternoon and all was going smoothly until my thread snapped......muttered away to myself about how I had just been reading this thread earlier. So, I went through all the usual remedies to no avail when after re-threading for the third time after thread breakage I pulled the thread down near the needle and watched it travel from the spool...... and what do ya thinks I saw peoples? I saw my thread coming off the spool so nicely and then, every couple of revolutions of the spool it snagged.....on a tiny bur on my plastic spool cap!! Never thought to check the spool cap for rough edges! Once I rubbed that errant little bit of plastic horror off the cap edge all went smoothly and I had no further trouble. Really, it was so small but it still protruded enough for my finger to feel it and obviously the thread to snag on! I've had this problem on and off for ages, always putting it down to haphazard gremlins but in reality it has always been it would seem, when I have used this particular spool cap and when I have inadvertently placed it on the pin with the burr uppermost where it would snag the thread! Who woulda thunk it eh??:shock::)