Why do we still use bobbins?

[MikeRock]

AlZilla

If you've ever seen the bobbin and shuttle on an old Landis Nr.1, the loop formed is big enough to throw a skunk through.  Hand crank or pedal, it takes time.  Wonderful machine, I love mine. Sew's 5/8", up to 3/4" of good harness leather.

Happy Thanksgiving to all.

[AlZilla]

1 hour ago, toxo said:

. The hook still picks up the bobbin thread and wraps it around the bobbin case for the next stitch as per normal.

No, because if there's a thread feeding into the bobbin case from below, the top thread can't go around the bobbin case.  You'd have to snake that bobbin thread down from the top ... Somehow.

I'm happy to be wrong so we can start using 1 pound spools for bobbins. I just can't see it.

You'd have to move the feeder thread for the bottom out of the loop forming top thread altogether. [EDIT: No, because you still have to loop the top thread around the bottom, it doesn't matter where it feeds from].

[toxo]

1 hour ago, AlZilla said:

No, because if there's a thread feeding into the bobbin case from below, the top thread can't go around the bobbin case.  You'd have to snake that bobbin thread down from the top ... Somehow.

I'm happy to be wrong so we can start using 1 pound spools for bobbins. I just can't see it.

You'd have to move the feeder thread for the bottom out of the loop forming top thread altogether. [EDIT: No, because you still have to loop the top thread around the bottom, it doesn't matter where it feeds from].

I can't understand what you're saying!!! We are talking about a normal walking foot machine with a horizontal bobbin right? The bobbin thread comes from below and interferes with nothing. Everything is normal. The hook comes around, picks up the bobbin thread, puts it through the needle loop and carries it around the static bobbin case for the next stitch. Explain what I'm missing.

[chuck123wapati]

If it could have been done, it would have been done years ago. Bobbins suck; engineers have known that since they were invented. But it's what it is, and some things in life we just have to deal with lol.

[AlZilla]

10 hours ago, toxo said:

I can't understand what you're saying!!!

Ok, KGG posted a video here https://leatherworker.net/forum/topic/132390-a-must-view-for-all-levels-of-sewing/ that has a large scale demo of the lock stitch, starting at 8:30. Watch it as the bobbin passes through the loop. It doesn't matter if the loop goes around the bobbin or the bobbin goes through the loop. It has to happen. It also doesn't matter if it's flat or vertical. The relationship is the same.

Now, as you watch the demo, imagine instead the hook pulling the loop around just the endless bobbin thread.  First of all, you'd have 2 strands of top thread going around the bobbin thread. Then one of two things would happen. Either the (Oscillating) shuttle would back out of the loop and the tension arm would snatch it all back topside. Or, the (Full Rotary) hook would keep spinning and wrap the top thread around itself, while the tension arm tried to snatch the top thread back to the topside.

I don't know how else to explain it and I'd LOVE to be proven wrong.

 

[toxo]

4 hours ago, AlZilla said:

Ok, KGG posted a video here https://leatherworker.net/forum/topic/132390-a-must-view-for-all-levels-of-sewing/ that has a large scale demo of the lock stitch, starting at 8:30. Watch it as the bobbin passes through the loop. It doesn't matter if the loop goes around the bobbin or the bobbin goes through the loop. It has to happen. It also doesn't matter if it's flat or vertical. The relationship is the same.

Now, as you watch the demo, imagine instead the hook pulling the loop around just the endless bobbin thread.  First of all, you'd have 2 strands of top thread going around the bobbin thread. Then one of two things would happen. Either the (Oscillating) shuttle would back out of the loop and the tension arm would snatch it all back topside. Or, the (Full Rotary) hook would keep spinning and wrap the top thread around itself, while the tension arm tried to snatch the top thread back to the topside.

I don't know how else to explain it and I'd LOVE to be proven wrong.

 

Woah! Where did moving shuttles come from? I'm talking about a standard machine where the bobbin simply rotates as a reaction to the thread being pulled by the hook. apart from this rotary movement the bobbin doesn't move at all. It sits inside a bobbin case that doesn't move at all. the bobbin thread goes through a slit and a tension mechanism that also doesn't move. In short, the ONLY thing that moves is a revolving hook. Now imagine a bobbin that doesn't move at all. In fact imagine NO bobbin at all, just a thread coming from a cone somewhere and going through the same slit and tension mechanism as normal. The only fly in the ointment that I can think of is getting the cone thread coming up from below somewhere into the tension mechanism WITHOUT interfering with the hook and I'm sure there are many minds greater than mine who can work that out.

[AlZilla]

1 hour ago, toxo said:

think of is getting the cone thread coming up from below somewhere into the tension mechanism WITHOUT interfering with the hook and I'm sure there are many minds greater than mine who can work that out.

I believe we've said the same thing ...