So what did I find?
 

I found this in a box of sewing machine needles I know that it cuts fabric with a wavey edge looks like it mounts to the needle bar somehow. Any information is appreciated.

WOW, what an interesting gadget. Do you think it is like a serger?? It certainly appears that it attaches like my Bernina walking foot.

Not sure I think it would set to far away from the needle for that. I was thinking it might be for cutting strips for rug making?

It's a machine-driven pinking attachment.

CD in Oklahoma

What CD said. IIRC they're not common and they are collectible. Great find! Macybaby might be able to tell you if it's complete or what's missing.
Rodney

You are missing one important part - the spring loaded mounting screw. At one point there was someone making a replacement screw, but I don't know if they are still doing so.

They use pressure to cut, so you don't need to ever sharpen anything.

Here is a picture of the two I've got - hand crank and machine driven. The machine one, complete with box sells for $60- $70, then hand crank a bit less.

http://i31.photobucket.com/albums/c3...ps0dadaa23.jpg

There are different cutters you can get too, for slightly different patterns, but those are quite rare.

This is what the mounting screw looks like.

http://i31.photobucket.com/albums/c3...psmontwmam.jpg

So where or how do they mount on the machine?

Neat attachment. I have some images of the instructions and pdf for the hand crank. The images of the pinker attachment instructions are at http://www.newenglandsimpleliving.co...structions.htm April 1930s might have a pdf and I think youtube may have a couple of videos of the pinking attachment. I just googled "singer pinker attachment instructions" You could also try "singer pinking attachment instructions."
From my understanding there were actually two pinking attachments. The newer one has the allen wrench type tool for holding the gears to clean or change the blade while turning the thumbscrew in front of the blade. I have an older one that just has a nut and no place to stop the gear to change the blade. It didn't come with instructions so I haven't yet tried to get it apart.

I'm not sure if it will work with the extra long presser foot screw from sew-classic or not. I haven't tried it on the pinking attachment but it works as a stitch lever for my 1902 15k26.

Also, IIRC the thumbscrew to remove the blade is a reverse thread in that you actually turn it to the right (clockwise) to loosen. (I think there is an arrow on it)

Janey - Neat people never make the exciting discoveries I do.

I bought a hand crank pinker at a flea market last year. There was no C clamp or box. I am looking for the clamp-are there any identifying marks on the clamp? I would think that maybe Singer would be cast into it? Thanks for any info you could give me.