Watch driver graduate before summer starts (10)
I believe the answer is:
mainspring
'watch driver' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'graduate before summer starts' is the wordplay.
I cannot really see how this works, but
'graduate' could be 'ma' (abbreviation for Master of Arts) and 'ma' is located in the answer.
'before summer' could be 'spring' and 'spring' is located in the answer.
The remaining letters 'in' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mainspring that I've seen before include "Principal agent of motivation" , "essential to watch" , "Chief motive" , "It motivates" , "motivating force" .)