By-pass fluid passageway for drill tool

A rotary drill tool for cutting rock comprising:

• a main body having a leg;
• a spindle projecting from the leg to mount a rotary cutter via a plurality of bearings, the plurality of bearings including a first set of roller bearings, a second set of roller bearings and a set of ball bearings, wherein the spindle includes a longitudinal axis, a base region, a base raceway extending axially between the base region and a bearing raceway, the bearing raceway having a concave external surface and extending axially between the base region and an annular shoulder and an annular section extending axially between the bearing raceway and an end of the spindle, the annular shoulder being positioned axially between the bearing raceway and the end;
• a fluid supply passageway extending through the leg and having a terminal end positioned in communication with a fluid directing passageway extending through the spindle, at least a part of the fluid directing passageway configured to allow at least some of the bearings to be loaded into position between the spindle and the cutter, wherein the cutter includes at least one vent hole positioned at or towards an apex of the cutter and a fluid received from the fluid directing passageway exiting the tool from the at least one vent hole;
• a by-pass passageway extending through the base region of the spindle, the by-pass passageway emerging at the base raceway and having a first end in communication with a section of the fluid supply passageway upstream of the terminal end and a second end that emerges from the base region of the spindle to supply fluid to the first set of roller bearings, the base raceway being arranged to mount the first set of roller bearings at or towards the base region of the spindle, the set of ball bearings being positioned at the bearing raceway axially between the first set of roller bearings and the end of the spindle, an end of the fluid directing passageway emerging at the bearing raceway, the second end of the by-pass passageway emerging at the first set of roller bearings, wherein the second set of roller bearings are mounted at the annular section towards the end of the spindle and the set of ball bearings are mounted axially between the first and second set of roller bearings;
• and
• at least one distribution passageway extending within the spindle and provided in communication with the fluid directing passageway, wherein the distribution passageway is divided into at least two passageways, a first passageway exiting the spindle at the shoulder and a second passageway exiting the spindle at the end.