Sewers using fine line for edges of cloth trousers (8)
I believe the answer is:
flannels
'trousers' is the definition.
(I know this)
'sewers using fine line for edges of cloth' is the wordplay.
I cannot really understand how this works, but
'fine' could be 'f' (abbreviation e.g. condition of old coins, books) and 'f' is found in the answer.
'line' could be 'el' (el is a kind of line) and 'el' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for flannels that I've seen before include "cloths for washing" , "Soaps" , "face cloths > for the cricket team?" , "Type of trousers" , "Provides soft soap" .)