Can you identify these blades?

[Puzzled]

These blades belonged to my father who was an agricultural engineer and who passed away last year. He told me that they are very old and I think may have come off of an old reaper or thresher?? They measure just under 87” in length but the blade section measures 6’ x 3.5”. Any help you could give in identifying these would be much appreciated.

 

[5020man]

Hi.
There are off a horse drawn grass mower. or grain reaper binder.
But, at 6ft long most likely the latter.