Of necessity, crepe for manufacturing (8)
I believe the answer is:
perforce
'of necessity' is the definition.
(I've seen this in another clue)
'crepe for manufacturing' is the wordplay.
'manufacturing' is an anagram indicator.
'crepe'+'for'='crepefor'
'crepefor' with letters rearranged gives 'PERFORCE'.
(Other definitions for perforce that I've seen before include "By force of circumstance, necessarily" , "Necessarily, arising from free crop" , "Necessarily; inevitably" , "Of necessity" , "willy-nilly" .)