Carbon in wrought iron is for cutter (7)
I believe the answer is:
incisor
'for cutter' is the definition.
(I've seen this before)
'carbon in wrought iron is' is the wordplay.
'carbon' becomes 'C' (C is the chemical symbol for carbon).
'in' indicates putting letters inside.
'wrought' indicates anagramming the letters (wrought means beaten or shaped into form).
'iron'+'is'='ironis'
'ironis' anagrammed gives 'inisor'.
'c' inserted into 'inisor' is 'INCISOR'.
(Other definitions for incisor that I've seen before include "cutter" , "Narrow-edged tooth" , "something with bite" , "Cutting tooth" , "One takes a bite" .)