I have a Viking Designer 1 machine. I've tried the L-Shape prewound bobbin and it works just fine. I already use Aurifill thread to help with seam allowance, but notice that the prewound thread is finer that the Aurifill. Has anyone ever successfully used the prewound bobbin thread for both top and bottom - or is it just not something that is not recommended at all?

Thanks,
Rhonda

thr threads considered 'bobbin-thread' are finer than regular sewing thread...usually the aurafil threads are either 40 or 50 wt...bobbin thread is 100 wt. (the higher the number the thinner/finer the thread...12 wt is like using string)
i keep the 2 separate, bobbin thread for the bobbin, 40-50 wt thread for the top...i did run out of white thread one time and used my 'sure-fine' bottom wt thread...it broke every 2-3 inches and made me a crazy person till i stopped and went to the store... i also have a designer one...my machine is very (picky) about threads...i have had some very expensive threads just not work...so, i have to say...use what works for you. if bottom line works on the top...good for you!

Like prewound bobbins. I have only used them for in bobbins not as top thread.

Merry Christmas

I only use prewound bobbins for embroidery. Mine are 60wt and that is to fine for quilt or constructuon.

I also have a Viking D1 and only use the prewound bobbin only in the bottom for the bobbin, never in the top thread as it is way too fine a thread. Don't you just love your machine?

I do. It saves my having to buy spools of colours I'll rarely use.

My Bernina takes them top and bobbin. I use Superior Threads' Bottom Line and have to rewind the bobbins onto a Bernina bobbin.
I like the thinness of 60; seams lie very flat.
My Jems will only take Bottom Line in the bobbin; the Jems take the prewounds; I use Aurifil spools on top for them or Superior's Masterpiece prefilled bobbins (a cotton).