Abstract: A tool for measuring the extent of decay in a wooden object, comprising an elongated probe adapted to be inserted in an inspection hole drilled in the wooden object. The tool has at least one barb protruding therefrom adjacent to one end of the probe. The barb is designed to engage a side wall of the inspection hole so as to shear wood fibers in the side wall as the probe is withdrawn. There is indicator mechanically coupled to the probe for measuring the amount of pull-force required to shear the wood fibers in the inspection hole. The indicator includes a deflector mechanically connected to the other end of the probe and adapted to provide a measurable deflection as the pull-force required to shear the wood fibers increases. In use, when the pull-force exceeds a predetermined value, the indicator provides an indication of a transition within the wooden object from decaying wood to sound wood.