Wooden handle, idea for file, BBQ skewer handle.
Made from wood with a metal collar (Collar retains the wood in the end of the handle and helps prevent the wood from splitting when tongue is driven into the end). 

Wooden handle 6mm center hole 130mm length, suitable for 8".10" files, the biggest OD is 30mm

Wooden handle 8mm center hole 130mm, suitable for 12", 14" files, the biggest OD is 31mm