Pfaff 545 Alignment of Bobbin case Cap & Base

[friquant]

How should the fingers of the bobbin case Cap align with those of the bobbin case Base?

Attaching a photo of the alignment I've got. The alignment looks off to me on two accounts:

1. the hole one the Cap is offset form the hold on the Base

2. The longest protrusion of the Base sticks out farther than the longest protrusion of the Cap.

The symptom is that when the thread comes around the bobbin, sometimes it gets caught on the outermost protrusion of the bobbin case Base, so instead of making a stitch in the fabric it has made a loop around the undercarriage.

With TEX 90 or TEX 70  thread the machine is usable, as then the above-named conundrum only happens if you pull excessively on the needle thread while hooking the bobbin thread.

But with TEX 30 it happens even during normal stitching...It might get five or six good stitches in before it locks up. (Not that I expect to be doing much stitching with TEX30, but we didn't yet have the color we wanted in a heavier thread.)

 

I'd be interested to see photos of alignments on other 545s, and especially to hear if anyone has adjusted/modified their alignment to make it work more reliably.

[nejcek74]

Pfaff 1245

Pfaff 1242

Pfaff 142

Are you sure you had the right bobbing case? Or the hook assembly? Maybe something was changed for a wrong or unoriginal part, I don't remember any setting for this, bobbin case just drops into the hook. Check the exploded view of parts for Pfaff 545 and the engineering manual for the Pfaff 1245.

[friquant]

8 hours ago, nejcek74 said:

Are you sure you had the right bobbing case? Or the hook assembly? Maybe something was changed for a wrong or unoriginal part, I don't remember any setting for this, bobbin case just drops into the hook. Check the exploded view of parts for Pfaff 545 and the engineering manual for the Pfaff 1245.

Your photos are super helpful! I like those alignments a lot better, as there is no way for the thread to get stuck.

The part numbers stamped on mine are pfaff 18348 (Cap), and pfaff 18346 (Base)

As for checking the exploded view of parts, I found this document: https://www.diamondneedle.com/documents/Pfaff Parts Manual/145_545.pdf but the part numbers in there all start with "91-010".

[nejcek74]

maybe take the hook apart and clean it:

you need to take the needle plate and the bobbin,

unscrew 3 little screws to remove the hook gib (91-018 439-05),

than you can wiggle the moving part of the hook (91-018 346-01) out,

unscrew the central screw and take the rest of the hook and washer out.

Clean everything, put a little bit of oil. Washer and the base of the hook have only one position how they can be put back. When you finally put he moving part of the hook (91-018 346-01) back, you need to be careful that the little extrusion is caught under the needle plate, it should be rotating only for few millimetres.

 

[friquant]

After carefully filing and polishing the end of the moving part of the hook, here is the new tip alignment (photo)

The original symptom is much improved. It will even stitch with TEX 30 now, so long as I'm careful while hooking the bobbin thread.