In the worst of case you can probably get chinese made replacements; they might be all fine, or they might need slight tweaking to run smoothly (like sanding down edges if the metal cut out isn't accurate enough). Either way, both the 117 and 540 are superb machines, and with a bit of time and patience you will find replacement parts at a more acceptable price. There were a few early German ziggzaggers, I think Mundlos might have had the first domestic zigzagger. Pfaff 130 came a few years later. There are a few vintage related groups on "groups.io", maby a few are still active on yahoo; they can be very helpful with info on where to get replacement parts. Don't forget Helen Howes in the UK, p&p isn't that expensive for small parts.

Thanks for those tips Mickey. I'll be intrigued to see if the 540 bobbin parts are the same as the 117. If they are I'll know exactly what to look for.

Jools, I have a 117K and can take some pictures. .
Have been looking at your picture and have a few questions
Do you have the feeddogs?
Do you have the shaft to hold the hook assembly and bobbin case? Comes out of the "box"

The washer looking item on the table appears to be the back of the bobbin hook assembly . We can't see the other "bits" in your picture. Could they be the rest of the hook?

Maria, thanks for your kind offer of advice / photos.
I'm out today, but I'll take better shots tomorrow so you can see more clearly what I have under there.

Well, now I have my 540 and have taken the bobbin 'area' components apart, with these conclusions:
It looks as if the 540 rotary needle and bobbincase are the same and will fit the 117. That's good! (The bad news is the cost of the ones on ebay!)
Take a dekko at this pic I've just taken of the 540 components.
http://imagizer.imageshack.us/v2/800...921/SJDsL2.jpg

Sorry if the pic isn't showing... it does in my preview, -I'll see if I can fix it.

I don't have the retainer circled, it holds the edge of the round backing plate that is screwed to the back of the rotary needle.
I'd need one of these retainers, though I could make one using this as a pattern.

Note that spring 'clip' thing arrowed. I can't see any function for this. It's screwed onto the 'box' and extends around to the side/rear of the rotary needle. The end of the spring spiral is not broken, (it is shaped and 'finished' but doesn't seem to go anywhere!). It wouldn't fit on the 117 anyway because the 'box' screws are arranged slightly differently.
(Sorry, I'm calling the 'box' the part of the underside casting with the square-ish cover plate, through which the shaft passes for the Rotary needle)

Yes Maria, I do have the feed-dogs and the shaft that the hook assembly is mounted to. Confirming that disc is the one screwed to the back of the rotary needle. All that seems right. See my other post showing my 540 components etc. (The image seems to be sometimes there and sometimes not!) And there's apparently a 20 minute time limitation for editing a post, so it may be hard to sort out!