Rivet or nut, crude (7)

I believe the answer is:

engross

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'rivet' is the definition.
(I know that engross is a kind of rivet)

'nut crude' is the wordplay.
'nut' becomes 'en' ('nut' is printers' slang for an en space).
'crude' becomes 'gross' (I can't justify this - if you can you should give a lot more credence to this answer).
'en'+'gross'='ENGROSS'

'or' is the link.

Can you help me to learn more?

(Other definitions for engross that I've seen before include "Completely absorb" , "Absorb the attention of (someone)" , "Totally absorb the attention of" , "Occupy attention fully, absorb" , "Rivet" .)

I've seen this clue in The Times.

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