Do top and bobbin threads have to match in weight?
 

I have read both ways, but for piecing and probably quilting, I have read here to put 50 weight thread in bobbin, don't remember exactly why, but more will go onto bobbin, for one thing. Other places I have read where top and bobbin thread must match in weight and "material", i.e., cotton vs. cotton wrapped poly, etc. Opinions?

I use pre-wound bobbins for embroidery machines for piecing. Lots of thread on the bobbin to keep me going.

Short answer is no, they don't have to match.

I usually use a thread made for bobbins, like Decobob or BottomLine, which are 60 weight and my thread of choice in the top.

https://www.superiorthreads.com/bobbin-thread

Watson

Doesn't matter, the machine doesn't care one way or the other. It's our thinking that makes it complicated. I use thin thread in bobbin, at least 60wt. The new thin threads are strong.

Wow, my ignorance on things sewing abounds, even after more than 60 years' experience! I just bought some Aurofil 50 weight cotton for bobbins, so apparently what I have been using is 40 weight ordinary thread? And now I hear 60 weight is even better? Yikes, there's always more to learn (for example, it was only a couple of years ago that I found out there were different size needles. . .). I must be a senior member based on age, not skill!

I am so happy to see the responses to this post. It certainly makes things more clear for me. Thank you.

I piece with 50 wt and most often use the same thread in the bobbin, just because that is the way I always did it. My machine doesn't really care.

I don't pay a lot of attention to that. It seems to work just fine either way. It is a good way to use up odds and ends of thread both on the spool and in bobbins. I often use a bobbin as my top thread on a vertical spool. I figure the more economical I am with thread the more money I have for fabric!

What ever I put in my top, I put in my bobbin. I don't want to have to worry about it. My machine tells me when I'm running low and is easy to change. I try to do extra bobbins when needed but my machine will wind them while its still threaded. I love Aurifil thread, I get more accurate seams using it. I do the same thing when doing embroidery. Its always the same type, depending on how much stabilizer I might be using I may have different colors as long as I'm sure it won't show thru.

I usually use the same in both but a lot of people use a higher count in the bobbin.

I usually like to use 50 wt for piecing, top and bobbin. I know there are people who prefer 2 ply 60 wt. because they feel it makes a flatter seam. Personally, I am not convinced it is strong enough for a quilt that is used. I like to use 40 wt King Tut or Sulky for quilting and usually use Bottom Line in the bobbin. I have used Sulky 28 for quilting when I really want the quilting to show up. I am experimenting with some of the new polyester threads for quilting. I do not like to use mettalics because of the shredding problems. It is important to use the right needle for the task at hand. Superior Thread Company publishes great information. They have done a lot of research.