>>2908639
So.. Three (3) Singer 201ks, a lot of sweat, tears and a solid 50+ hours of my life later.. It was the FUCKING thread. There's nothing mechanically wrong with (at least the newest) machine.

>using 201(a) perfectly except it has a loud rattle
>bulk buy a bunch of Gutermann 100% cotton thread
>get a new 201(b) that doesn't rattle
>try to fix original 201(a) so that it doesn't rattle, suddenly it isn't stitching straight
>double check the other 201(b) and realize it doesn't stitch straight either
>oh nooo I fucked them both up
>buy third 201(c) that is ALSO shit
>wowee how could this be? this one is definitely mechanically sound
>ask the internet
>one million "have you tried rethreading it" responses later
>"oh anon, you're using gutermann? 201s hate cross-wound thread"
>what the FUCK is that?

Anyway, here's a fun fact that I want everyone itt to know:
>Thread comes spooled either cross-wound or stacked (a straight spin like a bobbin.)
Stacked thread pulls smoothly when un-wound vertically from a fix position, like most vintage machine's spool holders.
Cross-wound thread catches and fucks with the tension unless it can un-wind horizontally - Either on a horizontal spool holder (modern machines' spool holders often have a hinge to tilt them sideways) or with a hook stand that pulls the thread vertically up off of the spool before feeding down into the machine's thread guides.

Pic related. I sincerely hope that this helps someone else out, because I had seriously reached a point where all of the joy had been sucked out of sewing for me and was ready to give it all up over this shit.