i think if there was a machine that worked well without bobbins, we'd all have one!!!

Years ago when I worked in a shoe plant sewing those stripes on those old black and white track shoes, my machine had an endless bobbin like that for all six seams. So, I had 12 spools of thread to deal with. It was great! I could sew and sew and sew. When I ran out of a spool, I'd just tie on another spool and pull it through and go again. Maybe they will come up with one if they haven't already. I'm sure going to find out when I buy mine.

I know it would be my dream...I get tired of having to go back a few feet to pick up where the thread ended.

A few years ago I was told by a technician at a sewing machine manufacturer that it can't be done due to the way the underside has to be constructed in order to grab the lower thread. He said it can't be done. However, in this technoligical age, can't is not a word.

Serger type machine don't have bobbins so it can done but. Put a serger on a frame?

There are some sewing/embroidery machines with endless bobbin such as the Singer XL6000 and others but I've never heard of a long arm that does it.

endless bobbin ???
 

It is not a long arm machine but my Bernina 820 has a bobbin that holds 1 1/2 times the amount of thread that an ordinary machine bobbin holds. It also has a large harp area & will count down the amount of thread that is left on my bobbin & I love that feature + many others.

Actually, it's 3 times the amount of a regular bobbin....or at least that's what I've been told.

There are other models that can wind a bobbin as this machine does. That's not an endless bobbin in the sense of what the OP is talking about. Google vintage dual spool sewing machine.

My husband has been trying to figure one out for years and hasn't. I think the big problem is going back and forth on the frame more than anything but then I don't know much.lol The M bobbin is the big long arm bobbin. I think if they ever figure one out it will be the big sale of the century!