Nut on beam in engine part (10)
I believe the answer is:
crankshaft
'engine part' is the definition.
(crankshaft is a part of an engine)
'nut on beam in' is the wordplay.
'nut' becomes 'crank' (synonyms).
'on' is a charade indicator (letters next to each other).
'beam in' becomes 'shaft' (synonyms. I am not sure about the 'in' bit.).
'crank'+'shaft'='CRANKSHAFT'
Can you help me to learn more?
(Other definitions for crankshaft that I've seen before include "Rotating part of engine driving the pistons" , "needed for a car" , "part of transmission" , "What will turn when driving" .)