shaft play, how much is bad??

[2fstcummins]

going to buy a silverbullet 66, how much shaft play is ok?
what all should i look at before i buy it? buying it from a private seller not new.

 

[rpainter]

in and out very bad.. up and down a little for oil passage. make sure the blades do not contact the housing

 

[malibu795]

should have less then .002" movement in either direction