What size bobbin thread???
 

This may be a dumb question but what size bobbin thread do you use? I have a Brother PE-770 embroidery machine and it uses 40wt. emb thread on top. Should I use the same on the bottom or not? I can't seem to find anything that gives the size of the bobbin thread including the machine manual. I've been using the prewound bobbins but I have to rewind them on a Brother bobbin otherwise I get a rat's nest. I tried using Bottom Line for the bobbin and that didn't work either. If I have to rewind the bobbins, I would rather buy the spools instead of the prewound.

MaggieLou - you did not mention if you were using the prewounds for embroidery or quilting. I also have a brother embroidery machine and the way I understand bobbin threads is that you use the bobbin holder with the colored dot for prewounds and the one with green paint on the tension screw for all other weights of thread. (Sometimes it is pink paint not green.) My prewounds are 80 weight and they work fine in my machine. I also have a spool of Brother bobbin thread for winding my own that is #60 weight - but I haven't tried it so cannot speak to that. In my classes for my new machine they taught bobbins this way - with the most important part being to change the bobbin holder for the type of thread being used. For embroidery I use the prewounds, for everything else I drop in the other bobbin holder and everything is great. Also, do you have a "washer" that you use below the prewounds? Prewounds are on a thinner bobbin (height) and the "washer" raises it up to the right height to feed correctly. Mine is metal and has a plastic spindle that pokes up through the center hole. Sorry - I don't know the correct term for what I'm calling a washer. I do know from experience that prewounds without the washer create a mess! Hope something here will help.

I finally found the correct name for the 'washer'; the correct name is bobbin guide.

I don't have different bobbin holders. My machine is embroidery only. No, I don't have one of the washers. I think the Bottom Line is 60wt but my machine doesn't seem to like it. If the prewounds are 80wt, that may be the problem. I can't seem to find the weight on any of the prewounds. I haven't tried the washers but that may help too. Thanks for your help.

I usually use the prewound ones except when I want the top and bottom to be the same color I use the same thread on top and in the bobbin