When Kurt Stroheim teamed with Art Nelson in 1970 they both used this. With
the opponent groggy,Stroheim or Art would climb to the top rope, clasp their
hands together and come down on the opponent like swinging an ax. Art Nelson
was still doing this manuever when he left JCP in 1975.
 
Depending on which one of the three JCP tv shows we were watching at the
time the move might be called "double ax handle", "double forearm smash" or
maybe even "sledgehammer".
 

You are welcome clawmaster. I will tell you something  concerning
the house shows I attended. The folks who wrote up the results for
the papers rarely got the description of the finish of a match correct.
Sometimes the way the articles were written it was almost like the
writer either was not there or they did not really know the holds or
manuevers. Usually the win/loss,draw,dq,countout or no contest were
correct but the descriptions of how it happened were not.There were
exceptions and I will say the sixties articles were the most accurate.