Various embodiments include an apparatus for servicing a turbomachine, along with a related servicing method. In some cases, the apparatus includes: a system for servicing a turbomachine casing having adjacent segments joined with a set of threaded fasteners, the system including: a threaded fastener tensioning device sized to fit over ends of a threaded fastener in the set of threaded fasteners, the threaded fastener tensioning device including: a retention component for retaining a first end of the threaded fastener; and a tensioner for tensioning or de-tensioning a second end of the threaded fastener; and a mounting system coupled with the threaded fastener tensioning device, the mounting system for retaining the threaded fastener tensioning device proximate the adjacent segments of the turbomachine casing.