Old-fashioned drier whiskey — double! (7)
I believe the answer is:
wringer
'old-fashioned drier' is the definition.
(old-fashioned device for drying clothes)
'whiskey double' is the wordplay.
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'double' becomes 'ringer' (I've seen this before).
'w'+'ringer'='WRINGER'
(Other definitions for wringer that I've seen before include "Old-fashioned clothes dryer" , "trouble when put through this?" , "Kitchen appliance" , "Old clothes dryer" , "A mangle" .)