Singer 66 looping thread--getting stuck on bobbin case/hook?
 

Thanks to this lovely board, I was able to work through the issues with my tension assembly--besides being assembled slightly backwards the beehive spring and tension disks were just worn out. New springs and disks and the thread is no longer jumping out of the disks at random.

But I'm still getting huge loops of thread and I think I've traced the problem back to the hook/bobbin area. ​​​​The thread keeps getting caught in the same place as it loops around. It makes about 10 huge looping stitches and then just gets stuck.

Any one run into this before?

It sounds like there may be a burr or possibly lint build up in the tension spring. There were a couple of differences between the earlier and later cases. Perhaps http://mysewingmachineobsession.blog...singer-66.html or https://archaicarcane.com/model-99-a...-dog-cleaning/ or https://archaicarcane.com/lessons-le...ing-the-twins/ would help.

Janey - Neat people never make the exciting discoveries I do.
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Are the loops on the underside of the cloth? And do you hear a snapping or clicking sound when the thread is being pulled around the bobbin?

I was having problems with that on my 401. It has the same kind of drop in bobbin system as the 66. I thought I had cleaned it well, but I was wrong. The thread was not only making a nest under the fabric, but the thread was looping around as it made a stitch and getting stuck. I would have to cut the thread to get the fabric out. Then I couldn't figure out where it was getting stuck. This is the thread I posted about it. This is the thread I watched that showed me how to clean the bobbin area.
bkay

I've had the whole machine disassembled for cleaning, so I kind of doubt it's lint. How would I get rid of a burr?

A huge nest of loops on the underside. And yes! The is a weird click or snap sound. Then the whole thing just stops and I have to cut it free. I'm guessing the click indicates where is going wrong?

I do not know all the actual names of parts, but I will try to describe them so they can be identified.



I had two different tension related problems, one on a 66 and one on a 99.



1. The first picture is of a newer 66; There are two assemblies which sit in the hook ring (which is the part that rotates during the stitch cycle), in the picture the part on the left is the bobbin case, and the part on the right (with the bobbin lift button and red felt oil wick) I am calling the bobbin case spacer; I had loosened the screw marked with the arrow on the bobbin case spacer (which the manual says you should never do but which I didn’t know at the time because I hadn’t read the manual) which allows the spacer to move under that tongue and change the gap between the case and the spacer through which the thread passes; when I had it assembled incorrectly the thread would snap through this gap after wrapping around the bobbin case, because it was too tight, during the stitch cycle, but I was able to get it adjusted correctly so the spacer floated a little more; older 66s that I have owned do not have the same spacer assembly and were not adjustable;



2. The 2nd picture is of the upper tension assembly; the problem I had on a 99 was that the spring, marked with the arrow, was too tight in the assembly in terms of tension such that it would not move freely through the arc and would not move below the thread guide on the left marked with the arrow; this caused the thread, when wrapping around the bobbin case during the stitch cycle, to be too tight and then snap through gap once it made it that far; I had to adjust the spring and the assembly two ways:

a. by changing the spring location relative to the splines on the inside of the center shaft of the assembly (there is a small prong bent off the inside end of the spring which catches in the splines), and

b. by rotating the entire assembly in the housing of the machine via loosening of the set screw marked with the arrow on the right, but not really visible; it took some adjusting but I was able to get the tension spring to move freely and completely through the arc which eliminated the snapping of the thread down around the bobbin case.



This was all trial and error, mostly error as evidenced by having to fix it all upon reassembly!

I'll second what Joe said. I'll lean towards the upper tension assembly if you've had dissembled. Could be the check spring position, it should be held at 2pm when tightening up and then move spring into the left hand recess to gain the right spring tension to start off with https://cdn.quiltingboard.com/images...es/thumbup.png

This board continues to amaze me. Both JoeJr and Hooligan were right. The tension uptake spring wasn't in quite the right position and the bobbin case spacer was WAY too far back. She sews like a dream now. Thank you!

@ThreadTheory Happy sewing https://cdn.quiltingboard.com/images...es/thumbup.png