Engineer's first in old bank for machine parts (8)
I believe the answer is:
bearings
'machine parts' is the definition.
(a bearing is a machine part used for rotation)
'engineer's first in old bank' is the wordplay.
I cannot quite see how this works, but
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is located in the answer.
'bank' could be 'earn' (to bank a sum can informally mean to earn it) and 'earn' is found in the remaining letters.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
(Other definitions for bearings that I've seen before include "specific location" , "locations" , "Part of machine" , "(One's) orientation" , "(Sense of) one's position or direction" .)