Hi, new to the forum I have a problem with my 842 , I was out felling some trees and the chain suddenly came off. On inspection the shaft holding the washer on the outside edge of the drive sprocket had fallen out. What I want to know is, is this shaft the crankshaft or does it screw into the crankshaft? I guess if it is the crank then it will be new chainsaw time as it is probably more than a new machine.