Turn to honed instrument in the end, sharp (2,3,3)
I believe the answer is:
on the dot
'sharp' is the definition.
(both can mean promptly)
'turn to honed instrument in the end' is the wordplay.
'turn' indicates an anagram.
'in the end' indicates one should take the final letters.
The final letter of 'instrument' is 't'.
'to'+'honed'='tohoned'
'tohoned' is an anagram of 'onthedo'.
'onthedo'+'t'='ON THE DOT'
(Other definitions for on the dot that I've seen before include "At precisely the right time" , "Absolutely punctual" , "Prompt" , "Promptly" , "Precisely punctual" .)