You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
alternatehistory.com
What if during the viking endeavors to North America there was just enough contact between the norse and the natives that the natives were able to learn and adopt some of the tool and weapon making from them?
The Vikings would have still leave like in our times but there'd be about 500 years for that remaining know-how to spread across the various native groups prior to the next European groups to arrive.