Yesterday I got my hands on a 1952 206k. It belongs to a friends neighbor who got it back from family members. It belonged to her mother. I cleaned and oiled it, then found a 221 cord so we could try it out. Either she has the wrong bobbin case or I just couldn't get it in right, it kept spitting it out.
I'd love to hear from anyone who could give me an insight into the bobbin area. The screw that holds a lever in place is very worn, my DH's big truck screwdriver might help me get it loose as its is a very substantial screw and worn to boot.
Can't tell you how thrilled I was. Back home, I looked up the serial # and found it was authorized October 1st, 1952, in the Scotland factory. It has a red sticker when you lift it up that says Repossessed Machine. It would take a manual to figure out how to work the zigzag, an arm goes across the back.
I'm encouraging her to get the cord rewired(her DH is an electrician) and compare the bobbin case to those available online. Then we'll have another go at making it her favorite sewing machine.