American Black Walnut Cracker ????

[glenn bradley]

These have worked my whole life ;-) K.I.S.S.

 

[Jim DeLaney]

These have worked my whole life ;-) K.I.S.S.

Then you've never tried to crack an American Black Walnut.
A machinist's vise or an arbor press will work.
A 12 oz. ballpein hammer bounces off them.

 

[Darren Wright]

These have worked my whole life ;-) K.I.S.S.

I did try those. It was like opening a submarine with a can opener. Black walnuts are hard!