Thank you, Greenshoots, for the link. Appears that a useful design gets picked up and used all over the world.
At least when you buy one, you buy somebody else's design idea and a pattern. Then you're better off to make your own.
Even a totally crapped out rusty handsaw blade would be nice sheet metal to use.
To the Inuit, the ulu or umialak is the woman's camp knife. They have and use straight edges as well.
I don't know about the edges used by the Aleut people or the others in the Eastern Arctic.