Iron law about right for cap put on stick? (7)
I believe the answer is:
ferrule
'cap put on stick?' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'iron law about right' is the wordplay.
'iron' becomes 'Fe' (Fe is the chemical symbol for iron).
'law' becomes 'rule' (rule is a kind of law).
'about' is a charade indicator (letters next to each other).
'right' becomes 'r' (common abbreviation).
'rule' after 'r' is 'rrule'.
'fe'+'rrule'='FERRULE'
'for' is the link.
Can you help me to learn more?
(Other definitions for ferrule that I've seen before include "Metal band on umbrella" , "Protective metal cap" , "Metal band on the tip of a stick" , "Metal cap on end of stick" , "Cap for protecting the tip of a walking-stick" .)