Hard wood needed for steering apparatus (4)
I believe the answer is:
helm
'steering apparatus' is the definition.
(I've seen this before)
'hard wood needed' is the wordplay.
'hard' becomes 'h'.
'wood' becomes 'elm' (elm is a kind of wood**).
'needed' says to put letters next to each other.
'h'+'elm'='HELM'
'for' acts as a link.
(Other definitions for helm that I've seen before include "Position of steerer" , "Steer (a boat/ship)" , "Ship's steering apparatus" , "Tiller, steering wheel" , "Steersman's place" .)