Constabulary

its actually 111w155 - I doubt there is a mechanical difference, maybe its a different plating on the metal parts (chrome vs nickel or vs blueing or something) either of the parts will work, I´m very sure about that.

I may have an original one - will check in the days to come.

I´d say this new fancy Pfaff machine range is not wide spread already. I doubt there is much experience with this type of machine yet. But why should a top class manufacturer like Pfaff have needle bar issues? Well, you never know but I seriously doubt this cause they for sure have experience from the older models and why should a simple part like a needle bar cause issues? If there was / is a known issue then your Pfaff dealer should know about it and should provide a replacement.

Adler 20 And Singer 7 are "quite equal" if that helps... A modern variant of the Singer 7 is the SEIKO SLH-2B (kind of) https://www.college-sewing.co.uk/parts-by-machine/seiko-sewing-machine-parts/seiko-slh-2b-2b-1-2b-fh1-parts.html?p=2

But you can print it out 😆 may take a few moments... 😉

what parts do you have?

thanks, did not know what to look for 😉

Posting an AliExpress link may help 😉

Try the "tension release disc" from the old tensioner (the one with he small bar across the center hole) - just a guess. Looks like this one: https://armastore.eu/32572-singer-tension-release-disk

just an other option - a thread oiler / lubricator may help too.

Download for a 133K manual but not exactly for the 133K13 but it may help: https://leatherworker.net/forum/topic/56667-singer-133k-information-wanted/page/6/#findComment-546077 the 2 parts on the left are positioning fingers and you notice the gap, right?

I guess you alreday have figured that is is a darning machine that ex factory is not set up for sewing operations. I once owned 133K3 but it´s long gone. There it a Bobbin case positioning finger that holds the bobbin case in position. You see it in your picture (that part is the "bar" above the hook / bobbin case in your picture). The top end of the bobbin case has to sit in the gap of the positioning finger (remove the needle plate and you have a better view on it and I think you will know what I mean when you see the gap). You only can insert and remove the bobbing case when the hook is in the right potion and you have to flip the bobbin case retainer aside before you can insert the bobbin case. EDIT: hope this helps

I´d check the needle bar height (needle hook timing) after 10 yrs the needle bar could have risen a bit and maybe you have to lower it a bit but that's just guessing. But needle bars rise with the time, that happens and is not unusual.

It has no feed dog so in which way do you think you can use a darning machine for leather work?