Abstract: A single piece hat-shaped catchment device for preventing machine parts and tools from falling into the inaccessible interior of a mechanism during the servicing thereof. The catchment device includes an inner section defining a central hole and a plurality of radially disposed segments, and an outer section defining a stop for limiting the depth to which said inner section can penetrate into the interior of said mechanism. During servicing the device is pushed downwardly over the exposed part of the mechanism to form an annularly disposed catchment trough for machine parts and tools. After servicing has been completed and any dropped parts or tools have been removed from said trough, the device is quickly and easily pulled upwardly off of said exposed part to permit the mechanism to resume normal operation.