Wrong to follow king round - it's essential to bow (5)
I believe the answer is:
'essential to bow' is the definition.
(used in making violin bows)
'wrong to follow king round' is the wordplay.
'wrong' becomes 'sin' (I've seen this before).
'to' says to put letters next to each other (I've seen this in other clues).
'follow king round' becomes 'ro' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sin' after 'ro' is 'ROSIN'.
'it's' is the link.
Can you help me to learn more?
(Other definitions for rosin that I've seen before include "Violin bow treatment" , "It's used on a violin bow" , "Fiddler's resin" , "Colophony" , "What gives bite to strings" .)