How to Replace The Carbon on a TS420 Cut Off Saw

Set the Stihl saw on a flat work surface such as a truck's tailgate, the ground or a work bench. Turn the saw so that the drive belt cover faces you and locate the bore hole near the front tip of the guard. Slide a metal pin, which comes with the Stihl saw, or small nail, if the pin is missing into the hole and spin the blade until it fully locks the wheel into place.

Turn the Stihl saw around so that the hexagon bolt that secures the abrasive wheel to the spindle faces you for easy access. Attach a wrench to the hexagon nut snuggly to avoid stripping the nut. Turn the wrench clockwise to loosen the nut. Unthread the nut the remainder of the way by hand and set it to the side. Remove the washer and set it next to the nut.

Grab the bottom edge of the carbon blade and tilt it toward you to remove it from the spindle. Slide it down to maneuver it from under the upper guard.

Insert the new carbon blade in the same manner as as you removed it and slip it over the spindle. Slide the washer over the spindle. Spin the washer until the spindle grooves slip into the washer; catche and lock into place. Confirm that the threads of the nut are clean of debris and dust, then thread the nut over the saw spindle in a counterclockwise direction until it's tight.

Attach the wrench to the hexagon nut and fully tighten it. Inspect the washer, nut and carbon blade to make sure they are all sitting flush together.