Nuts harder than steel

It must be true! We have a nutcracker of the type that screws down to apply pressure to the nut in a controlled way - so it is possible to crack walnuts without applying immense uncontrolled force then shattering them all over the kitchen.

Fine, except that the steel thread has stripped working on the latest batch of nuts from the supermarket. Maybe the thread should be made of reconstituted nut shells?