A turbomachine rotor blade milling machine system includes a fixture having a body including first and second opposing surfaces and a slot. The fixture is configured and disposed to connect with first and second rotor blade sections mounted in a rotor wheel. A mounting system includes at least one mounting element coupled to one of the first and second opposing surfaces of the body at the slot. A milling machine is coupled to the one of the first and second opposing surfaces through the at least one mounting element. The milling machine includes a cutter and is configured and disposed to form an opening extending axially through a dovetail portion of a third rotor blade section arranged between the first and second rotor blade sections.