There are other kinds of crushers, such as hammer crushers, which use huge plates or protrusions on spinning wheels to smash whatever is being crushed into bits. However, these are used most often in industries that are crushing rocks. Auto recyclers might use them to render scrap metal into smaller pieces, but this is rarely the first step in the recycling process for a car.
Some stationary crushers use a large electromagnet on a lifting arm to "grab" metal cars and drop them into the crusher. Shredders also use magnets to separate steel parts from non-ferrous materials.
Car crushers must be made with thick, hardened steel. The material has to be tougher than whatever it is they're crushing. This toughness is the reason that some of the original crushers made in the 1970s are still operational today.
To buy your own car crusher (great entertainment at backyard cookouts), plan on shelling out at least $30,000 for an older, used model. A brand new crusher will cost between $120,000 and $150,000.