An Etymological Dictionary of the German Language/Annotated/Schaft
Schaft (1.), masculine, ‘shaft, handle, trunk, stalk,’ from Middle High German schaft, Old High German scaft, masculine, ‘shaft, spear, lance’; compare Old Saxon skaft, masculine, ‘spear,’ Dutch schacht, masculine, ‘quill, shaft of a lance,’ Anglo-Saxon sčęaft, English shaft, Old Icelandic skapt, neuter, ‘pole, spear’; Gothic *skafta- is by chance not recorded. These substantival cognates can scarcely be related to schaffen, they are connected rather with schaben (literally ‘that which has been scraped or made smooth’?). It is most closely allied to Greek σκῆπτρον, ‘staff,’ akin to Doric (Pindar) σκᾶπτον, σκήπων, ‘staff’; further Latin scâpus, ‘shaft’; hence Old Aryan skā̆p-, ‘shaft.’
Schaft (2.), masculine, ‘shelves, bookcase, Modern High German only; from Middle High German schaf, ‘vessel for containing liquids’?. For the latter see Scheffel.