Helping my son with a house cleanout...this followed me home (no, not the pen; the rust). From the rough handles and general finish, it looks blacksmith made. It's still surprisingly sharp under the rust. The edge fits into the groove on the opposite handle; for a couple of inches from the pivot end, the groove opens to the other side, but it's mostly closed Any idea what it is/was?
Unless I find out it's valuable and I can retire* from the proceeds selling it on That Auction Site, it'll likely be available to the first person who'll pay for postage.
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*Oh, that's right; I am retired.