Chainsaw Repair

I've noticed on old bars where the chain lays back on the bar after leaving the drive sprocket there becomes a notch in the rail. The same notch is on the nose of the bar behind the nose sprocket.

I consider it a problem when the nose sprocket becomes worn to the extent that the chain rides on the rails of the nose rather than the teeth of the nose sprocket.

When you finish a cut and seeing the chain drooping underneath the bar . . . This loose chain was on top of the bar at the heel area when the saw was in the cut.