Collectors mount them on hinges (6)
I believe the answer is:
stamps
'hinges' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for stamps that I've seen before include "Brings one's foot down heavily on the envelope" , "Brings foot down heavily onto the ground" , "Postal tokens" , "Tramples" , "Gummed receipts of postal fees" .)