A 
machine for drilling oil-holes in crankshafts and the corresponding procedure. It can be used to 
drill one, two or more crankshafts per cycle. Each 
crankshaft can revolve on its own axis. The unit described is mounted on a horizontally-faced rotary table with vertical rotating axis, to place the crankshafts at different angles to the Z axis of the 
machining module, maintaining the horizontal position of the longitudinal axes of the crankshafts. Facing the unit is the 
machining module, provided with two horizontal spindles, 
drill tool-holders, with their corresponding guide bushings and parallel to each other, one on top of the other, at the same distance as the two crankshafts. The module has movement in three co-ordinates: axis X (horizontal-transverse), Y (vertical ) and Z (horizontal-presenting tools). A fourth axis W, (with additional module and 
independent action), moves parallel to Z and carries the guide bushings. It is provided with an automatic 
changeover, (tool+
bushing or just the 
bushing), incorporating simultaneously the pair of spindles.