Singer Merrit 4525 nesting
 

I usually fiddle with the Kenmore machines but this fell in my lap.
I have cleaned and oiled.
Sews great then suddenly i get nesting on the bottom. I have removed the tensioner, cleaned and inspected. Reinstall adjusted. Still the thread binds in the discs coming out of the tensioner somehow but not all the time. I have changed the spring/discs but it still happens.
I want to fix this issue before I donate it to someone.

So it rained all day yesterday so I dove back into it. I've determined it has to be something within the bobbin case area causing the upper thread to hang up causing it to get pulled deep into the upper tension disc.
With evidence on the hardware I can see someone has been in here. I think the needle shaft needs adjusting, looks like it goes way too low. I couldn't find in any of my files or online the spec for it so I eye-balled it and tweaked the hook timing.
It's way better but I'm still hearing and can feel a hang up. I checked for burrs. The bobbin case seems to be sloppy where it sits.
There is a plate next to the bobbin case that the tread must slip between. What's the adjustment on that? I've ordered a new bobbin case.
https://i.postimg.cc/85SZs5VB/4525.jpg

Found this....keeping my fingers crossed.

Setting the Singer Sewing Machine Apollo Bobbin Case

Nice! Thank you for updates.

Janey - Neat people never make the exciting discoveries I do.

Sooooo after adjusting the bobbin plate the machine jammed up and I was able to remove the bobbin case/carrier with the nest attached. I was able to discover where the thread was getting hung up on.
https://i.postimg.cc/bwHf4CkN/20221003-102907.jpg
I never noticed this blemish on the underside before. New "Singer" part should arrive Wednesday.
https://i.postimg.cc/kXSmvX5S/20221003-103011.jpg

Good that you have a new one coming.

Janey - Neat people never make the exciting discoveries I do.

The new bobbin case has arrived. I was disappointed that is wasn't a Singer OEM part as it was advertised.
However, I installed it and guess what? No more nesting!
I even went as far as removing and disassembling the electric motor to give that a good cleaning (it was struggling).
I also overhauled the foot controller, what a difference.
This machine now stitches beautifully and runs fast as it should.

Now to find a new home for it.

Great!!!:thumbup:

Janey - Neat people never make the exciting discoveries I do.