The present invention enables the diamond coating of stationary elongate objects, such as twist drills, with a continuous uniform film without any motion of the twist drill due to the unexpected superb "throwing power" of a reactor disclosed herein. The CVD diamond reactor includes a vacuum chamber, inlet for feed hydrogen/hydrocarbon mixtures, and an outlet, in conventional fashion. The improvement for coating with CVD diamond the entire outer surface of at least a portion of a plurality of stationary elongate objects comprises disposed within said reactor, an elongate metal tube having a plurality of apertures for holding elongate objects disposed radially inwardly and having a cooling pipe in thermal contact with and disposed about the outside of said metal tube; and a filament running within said tube along its lengthwise extent and being in electrical connection with the source of voltage for heating said filament to a temperature adequate to initiate hydrocarbon disassociation, the portions of said elongate object within said tube surrounding said filament being heated thereby.