Having recently worked on a 319 with a similar configuration (rotary hook with a stationary finger) I was able to re-assemble this. But not until I had cleaned the hook.
I took that apart. It was easy. The two little screws came right out.
I scrubbed the hook with a honing stick, some sand paper and denatured alcohol. I did the same for the bobbin case base. I put it all back together. It wasn't right. The bobbin case base was too loose. I took it apart and fiddled with it and got it right. I bet I spent more than an hour on this part alone. But this is the crucial part. No point in skimping here.
This was where I panicked a little. I took the hook off of this machine eight months ago. I was sure that I took photos but was too lazy to fetch the computer and look at them. So I figured it out. The shaft had a flat. There was one set screw missing from the hook. I usually remove the set screw that houses the flat when I take off a hook that sits on a flat (e.g. FW) I replaced the hook positioning the vacant screw hole over the flat and tightened both set screws (I was clever enough to keep all of the screws). It seemed to work.
I also had to reassemble the presser foot bar, spring and presser bar lifter. I set the presser bar height at exactly one EPIF (Elizabeth Perry Index Finger) height above the feed dogs.
The feed dogs were filthy. I had to soak them in degreaser, scrub with a wire brush, pick out the lint with a dental picke and rinse in denatured alcohol. They are stained, but clean.
I threaded the machine, guessing for the most part. I have a manual for it; downloaded from ISMACS, but I did not have it in the shop. Since it worked, I must have threaded it correctly. Threading is the same principle from machine to machine. Once you have an idea, you can pretty much figure out any machine.
It is about as clean as I can get it. The machine was commissioned in 1916. It has had a hard life. But it stitches. That, there, is a miracle.
