When I bought my $25 Craigslist sewing machine, I managed to get it sewing again relatively quickly with some basic cleaning and lots of oiling. Unfortunately, the bobbin winder refused to work. I popped the bobbin on the post, threaded it just fine, unscrewed the clutch (silver wheel in the middle of the hand advance), clicked the stop lever over into the bobbin, and nothing happened:
The motor turned, but the bobbin just didn’t spin. A quick investigation showed that while the stop lever itself moved, it didn’t affect anything on the underside of the assembly. It’s supposed to push a little rubber tire over to connect with the rest of the machine, but that wasn’t happening.
The logical step was to take it apart and see what was wrong. The first obvious thing was that it was about as filthy as I have begun to expect from this machine, but with more fuzz and less gooey stuff:
I tried to clean it with cotton swabs, but I just couldn’t get into all the crevices. The bobbin winder still looked filthy, the rubber tire didn’t move when I clicked the stop lever over, and the pin only turned very stiffly. So I held my breath and took it completely apart.
Most parts were easy to clean, and I was happy to see that both springs were in good shape, since I had suspected a broken spring might have been the reason that the bobbin winder wasn’t working. It was hard to tell as I was loosening screws and dealing with lots of grime, but I think the large spring may simply have become unseated. Another issue was the serious stiffness of the winder. I put a drop of oil on both the top and bottom of the sleeve that holds the rotating pin, and that helped a huge amount, but I noticed that as I was oiling, black residue was getting flushed out. I spent two entire episodes of Doctor Who oiling, spinning to distribute the oil, and wiping up excess as it flushed out the system. It was pretty gross. I don’t think I got it all, but at least the pin seems to spin freely now with all of this black grime flushed out.
(And, yes, those are the remains of the Manhattan that was M’s contribution to this part of the process.)
Next came reassembly. It was a bit fiddly, and I’m kicking myself for not taking more photos. But here’s the general idea: First align the lower part of the assembly, including the winder, stop lever plate, small and large springs, and the base, and screw together. Check the alignment on these parts, and then finish the assembly by screwing on the stop lever. Piece by piece:
- Seat the large spring into the hollow in the winder. Make sure that one end goes into the little hole in the bottom of the hollow; as far as I can tell, the large spring doesn’t have an “up” or “down.”
- Insert the small spring, pin end out, into its hole in the base and set aside for now.
- Set the stop lever plate onto the winder. Thread the other end of the large spring through the little hole in the stop lever plate, and make sure that the tab of the stop lever plate seats into the hollow in the winder. This part is tricky, but doable.
- Insert the longer of the stop lever & stop lever plate screws into the aligned holes in the winder and stop lever plate.
- Align the stop lever plate and winder assembly on top of the base and small spring assembly. Push the small spring in to fit under the tab of the stop lever plate and screw the two pieces together until hand tight. This part was the worst. I didn’t have enough hands, and ended up needing M’s help holding the whole thing together while I tightened the screw.
- Take the shorter of the stop lever & stop lever plate screws and attach the stop lever to the base, aligning the lower tab into the notch in the stop lever plate. The screws should be snug, but should still allow the lever to move.
Check your work by clicking over the lever, and seeing that the rubber wheel moves.
This whole thing gets reattached to the top cover with the base screws, and will wind a bobbin like a champ. Now to figure out what to do with that acursed broken reverse lever…
EDIT 29 November 2013
For reference, point A is where I was oiling the winder, and point B is where I was wiping up the excess.