more importantly, are you able to use the machine now ? I think they stitch really nicely. Hope you enjoy yours as much as I do mine !

Yes, the machine works great, but I will continue to try to get the other bobbin winder to work and I will try to get the other 128 to work, also. I have a collection of vintage machines and I love them all. I hate to see one that isn't working as it should.

Surfergirl:

I have a bobbin winder that gave me fits at first too. Did you take the time to clean the worm gear and the teeth on the drive cog? Did you oil it?

When you seat the worm gear into the cog... it has to have some play or it will just jam up. Also check to see that there is no grim or thread bits jammed into the mechanism. In my case there was a bit of black thread caught up under the screw on the back of the drive cog.

Do you need an adjustment guide for your 128? I can provide you with a link if you need it.

I recently bought a 128 the seller said was in "great or excellent condition" LOL So far I have found that the shuttle carrier was bent, the take up lever was bent, and the motor was/is weak.

I was having the same problem with the mechanism/ centre bolt of my Singer 127 bobbin winder binding up. I took out one of the washers, and it seems to be working well - thanks everyone! I couldn't quite figure out where the second washer was supposed to go...

bobbin winder
 

please remember that when the large toothed wheel on the bobbin winder is adjusted it will move the said wheel closer or further away from it counter part on the wheel spindle. there should be some slight play or looseness between the two teethed parts or it could break of said teeth on the wheel or make it harder for the tyre to turn. when the correct setting is found tighten the nut on the bolt to hold it in possition ,then the wheel can be adjusted to have light presure on the main balance wheel.
hope this helps as i am not good at explaining things.

Is it possible that the bobbin winder binds because it need oiling? Is the tire supple or hard as a rock?

It sounds like you're running into a classic issue with vintage Singer bobbin winders. When the winder tire tightens and stops the mechanism, it's often due to either the rubber tire being too stiff or worn out, or the alignment between the winder and the balance wheel being slightly off. You might want to inspect the tire for cracks or hardness—replacing it with a new one can sometimes solve the problem entirely.

Also, since the Singer 128 uses a vibrating shuttle and a different bobbin setup than modern machines, getting familiar with proper bobbin placement and tension can really help avoid winding and stitching issues. Here's a helpful guide on how to put a bobbin in a sewing machine that walks through the basics and gives some extra tips for older models like yours.

Hope that helps! Let us know if adjusting the tire or checking the shuttle mechanism changes anything.