Nut cracker and a nut picking tool.

A nut cracker can be found at Dollar General Store.

Just make sure the walnuts are not green inside.

A vise.

The best nutcrackers imho are the screw type, usually made of wood, such as this. The shells are cracked in a controlled fashion, enough but not too much, while your hand over the opening keeps any pieces from flying.

I use a pliers to hold the walnut and then whack it with a hammer. It works best on a cement surface though, like a cement basement floor.

Oh, and crack it along the seams. I bet using a cinder block would work well if you don’t have a cement basement floor or don’t want to find a place outside that’s cemented. You can find a cinder block at your local brickyard or I bet Home Depot or Menard’s. It’s not fancy or anything, but hammer and pliers does the job.

We have a Butternut tree in our yard that drops hard nuts similar to the Black Walnut. And the nuts stain your hands too. But they’re delicious.

This is what I do. I gather some of the nuts in a rice (hemp) sack, tie it up, and put the bag in my driveway. I then drive my car over the nuts to crack them. It always works.

You can also use a big nutcracker, but then you can only crack one nut at a time.

Work out more. NSFW
(Not meaning to offend, I found it hilarious, this is social after all)