All About Pocket Knives

Found this out in my shop today in a box of C clamps.Marked,"VESI KNIFE SERRATOR San Francisco Cal. PATENT No.2444119"
The crank rotates a cutting tool that is supposed to put a serrated edge on a blade when you slide it through the slot.The way it is designed will only allow you to put about a 2 inch long serrated edge.
I tried it on an old blade but it didn't work.I think there is a piece missing as there are two threaded holes in the top;one on either side of the slot for the blade.No big deal;just another unusual knife accessory.

Pretty interesting item. An image I found showing the missing piece. Looks like a spring to push down on the blade.

Pretty cool, thanks for posting, Ray!

I usually use a chainsaw file to touch up serrations, it works in a pinch.

Interesting.
Has anyone here ever used one?