Cutting tool holder retention system

An excavation cutting tool holder retention system. The cutting tool holder retention system includes a cutting tool holder having a holder engagement surface and a support block having a tool holder bore into which the cutting tool holder is inserted. A pin having a pin engagement surface is movably mounted to the support block such that the pin engagement surface may be moved to engage the holder engagement surface. At least one of the holder and pin engagement surfaces defines an inclined surface such that when the pin engagement surface is moved to engage the holder engagement surface, the shank portion of the cutting tool holder will be drawn into the tool holder bore. In the preferred embodiment, at least one of the cutting tool holder and tool holder bore is tapered such that the cutting tool holder will be drawn and wedged into the tool holder bore of the support block when the pin engagement surface is moved to engage the holder engagement surface.