The invention provides a fastening system including a pin member and a key for engaging the pin member. The pin member includes a shank portion and a recess formed within an end face of the shank portion. The recess includes a plurality of splines and recesses that form first and second bearing surfaces oriented at angles. The key includes a key head having a plurality of splines and grooves that form first and second bearing surfaces oriented at angles. The plurality of splines and recesses of the pin member and the plurality of splines and recesses of the key are adapted to communicate with each other when tightening and loosening the pin member.