The gearbox is designed to be installed on a portable drilling machine
able to drill down to around 800 metres. The gearbox is powered by a two
stage hydraulic motor and allows the operator to either drill holes or
take core sample holes.
The box has been designed with the "Stilson and sledgehammer" operator
in mind. The only in-field maintenance required occasionally is replacement
of the output shaft seals, which are located in easy-to-remove housings
that do not affect any other aspect of the box. All bearings and lip seals
have jacking holes provided to ease removal of parts during overhaul. The
case is fabricated from laser cut plates and a flame cut ring, which are
bolted and doweled together. All bolts of each diameter are of the same
length.
