Abstract: A coupling apparatus for adjusting and axially coupling first and second shafts about a feathering axis, comprising a collar having an end face having a plurality of axial notches, an insert having an extended portion and at least one radial pin and a cam ring circumscribing the collar. The collar is securable to a free end of a first. The insert is securable in a free end of a second shaft such that the extended portion extends axially from the second shaft and are receivable in the free end of the first shaft such that the pins engage upon the notches so as to axially couple the first and second shafts. The cam ring includes a plurality of radial flange segments and is rotatable to engage the pins so as to retain the pins in engagement with the notches.