You hold the macadamia nut with the nutcracker or vise grip, rest it on a hard surface, and hit it with the hammer. I didn’t have to hit that hard, I think.

A Macadamia nut shell is hard so normal nutcrackers usually can’t open them or you have to get an expensive nutcracker for opening the nut. When i just used the hammer the macadamia nut bounced all over the room and still stayed intact. This is an inexpensive way to open them with common household tools, I think.

Source: http://healingmagichands.wordpress.com/2007/12/17/how-to-crack-macadamia... [2]