As Will states, the pivot must be made straight and polished before you start attending to wear in the plates. If the pivots are very bad and you need to remove a lot of material to get them parallel then they may even need to be re-pivoted. Just one word of caution, as William states most wheels can have 5 degrees of lean in the hole but make sure the escape wheel is a much better fit than that, its the one wheel that needs to be a good fit but loose enough to spin freely.
If there is anything you dont understand please ask, we are always happy to help 
Paul.
