Man of letters sending same? (6)
I believe the answer is:
mailer
'man' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'letters sending same?' is the wordplay.
'letters' becomes 'mail' (letters sent in the post or mail).
'sending same?' becomes 'er' (I can't justify this - if you can you should give a lot more credence to this answer).
'mail'+'er'='MAILER'
'of' is the link.
Can you help me to learn more?
(Other definitions for mailer that I've seen before include "Poster" , "novelist" , "Norman --, US author" , "writer from America" , "One putting armour on" .)