Adjusted by turning a nut with two keys (5)
I believe the answer is:
tuned
'adjusted' is the definition.
(tuning is a kind of adjusting)
'turning a nut with two keys' is the wordplay.
'two keys' can mean two substitutions for 'key'.
'turning' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'key' becomes 'e' (musical key).
'key' becomes 'd' (musical key).
'nut' after 'e' is 'enut'.
'enut' is an anagram of 'tune'.
'tune'+'d'='TUNED'
'by' is the link.
(Other definitions for tuned that I've seen before include "Of engine, adjusted to run properly" , "Got engine right" , "Adjusted (musical) pitch" , "(Of radio) set to a frequency" , "Adjusted frequency" .)