Fix support for pot after front falls off (5)
I believe the answer is:
Here is my best explanation:
'fix' is the definition.
(riveting is a kind of fixing)
'support for pot after front falls off' is the wordplay.
'support for pot' becomes 'trivet' (type of stand for hot dishes).
'after front falls off' means to remove the first letter (the letter at the front is removed).
'trivet' with its first letter taken off is 'RIVET'.
(Other definitions for rivet that I've seen before include "Pin for joining metal", "Fasten with metal pins - enthral", "Metal pin; engross", "Bolt for metal plates", "Enthral", "Metal fastening pin", "Steel-plate pin", "Fasten -- engross", "make fast" and "Joining pin".)