Wine barrel trimmed to make instrument (7)
I believe the answer is:
sackbut
'instrument' is the definition.
(early type of trombone)
'wine barrel trimmed' is the wordplay.
I cannot quite see how this works, but
'wine' could be 'sack' (sack is a kind of wine) and 'sack' is found within the answer.
'barrel' could be 'b' (industrial abbreviation) and 'b' is present in the answer.
The remaining letters 'ut' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'to make' acts as a link.
Can you help me to learn more?
(Other definitions for sackbut that I've seen before include "Old instrument" , "Medieval form of trombone" , "Early form of trombone" , "Old trombone" , "Ancient musical instrument" .)