Take the old bar along when you visit the saw shop , it probably needs to be dressed on a belt sander to true it back up . The chain won't usually make the cut go to one side , no matter how poor a filer one might be ! Now if you buy a new bar save the old one to file chaines on . Just clamp it in a vice , drop the drivers into the groove and file away . You will do a much better filing job without having to chase things around . Plus most vices are mounted indoors where it's warmer , or at least out of the wind . I used to manage a saw dealership , Huskys , Johnsereds , Stihl and Partner .