Engine part with nut on screw (10)
I believe the answer is:
crankshaft
'engine' is the definition.
(thesaurus)
'part with nut on screw' is the wordplay.
'part' becomes 'haft' (haft is a kind of part).
'with' means one lot of letters go next to another.
'nut on screw' becomes 'cranks' (I can't explain this - if you can you should give a lot more credence to this answer).
'haft' put after 'cranks' is '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" , "part of transmission" , "What will turn when driving" , "needed for a car" .)