I'm new here so I don't know where to post this question:
I've never handled a spacer key.. and have only seen pictures of them. I think they are required for some key cutters if you are going to cut a new key by code. I know the cheap Foley Belsaw key cutter requires these or another micrometer attachment to space the cuts correctly.
My question is, doesn't the spacer key look awfully similiar to a bump key? I'm not sure because I've not measured the depth of the cuts or the height of the teeth.