this sounds dumb but is it loaded in the right direction or have you switched bobbin thread ? also check to make sure that the area under the chrome plate is clear of thread pieces. i must have pulled threads for 1/2 an hour one night one my pr600.

 

Check your upper thread tension. Too tight causes it to pull back up instead of letting the bobbin "catch" it.

 

Alos Dirty Gummend up Needles and rotaries will not catch.
Clean Clean Clean and Clean Some more esp. if you are working with anything Sticky.

 

I have had this happen too and sometimes it is just a bad bobbin - try replacing it with a different one;

 

Thank you for all the suggestions. I cleaned underneath the chrome plate which did have a few threads. I ran the tension test stitches again and reset them a little. It was a little better but still not perfect. I ended with those hats and started on a different one with different colors of thread and the problem has gone away. This hat now sews out perfectly. Could it have been the brown thread or the type of hat? I am not completely done with these hats and am not looking forward to starting this particular one again! Thanks, again

 

Caps can be more of a problem because of the flex. Imagine your needle going down, the bobbin catching the upper thread and then as the needle comes back up the cap flexes back and pull the upper thread back up with it.

 

I was just doing a logo the other night and for about 2,500 stitches of tatami fill the machine didn't pick up any bobbin thread. It had already sew about 1,500 stitches with this color when it stopped picking up bobbin. Then when it changed color and went to put a satin border around the tatami it started picking up the bobbin. Very curious. Fortunately, since there wasn't any bobbin on the tatami it was easy to pull out and Peggy's Stitch Eraser took care of the satin border. I didn't change needles on the defective color or anything else after I had the thread removed. I backed up the machine to the point where it went haywire and tested the machine on some backing. Everything was fine. I backed up again, put the shirt back on the machine and the logo finished just fine. No idea what happened.

 

I had a serious case of the same thing happen when a piece on my rotary hook broke (don't ask). Replaced the hook with a new one, of course the timing had to be reset (which I did best I could) but the machine seemed to go downhill from there. After quite a while I nailed it down to my needles not being low enough. o don't laugh-- if anyone has other suggestions I'm open to 'em!!) I used to put them in till they stopped, but........ I played a bunch with the rotary hook position, but could NOT get the hook to line up in the middle with the needle scarf, therefore the bobbin thread wasn't catching.

Anyway......I don't know if that was a proper adjustment or if I still have a hidden problem, but for now I drop my needles +1/4" and haven't had a problem for several weeks now.

 

It almost sounds like something else must be going on. I can't imagine that the needles shouldn't be inserted all of the way. I would think not putting them in all of the way would introduce too much variability into the needle height.

 

Thanks, that's what I was wondering. Really the idea doesn't make sense (duh!!), but I was at a loss at what to do, and it works fine now. Hmmmm...... But that's subject for another thread (no pun intended ), I don't mean to hijack this one.

I forgot to mention last post, hats were also my biggest problem with thread not catching. Craig's explanation makes sense.

 

euh embroidery fot dummies: is bobbin thread the same as just thread??
Excuse me for my dum question but English is not my native language.

 

You might think about getting a needle depth gauge. If changing the depth freehand gets the needle sewing again then I'm sure thats the problem.

 

When I have those issues it is usually due to lint somewhere in the thread path.

 

The rotary hook is not in the right position and that is why you have to lower needle. The position around it's circumference and distance from needle front to back are critical.Larry

 

So I have Barudan pro II and it was cutting the bobbin thread too short. When it went to start again after the cut it wouldn't grab the bobbin. So I took off the metal plate, opened the part with the velcro a little. Then I adjusted my knife arm from the back off the arm so the knife in the hole was moved more forward. It then worked fine, the bobbin thread is now being caught by the velcro and it is working fine. Just wanted to let you know what worked for me.