Balances more than one pound; needs nerve at the start (10)

I believe the answer is:

steelyards

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'balances' is the definition.
(I know this)

'more than one pound needs nerve at the start' is the wordplay.
'more than one pound' becomes 'yards' (pound can mean a yard or enclosure).
'needs nerve' becomes 'steel' (synonyms. I am not sure about the 'needs' bit.).
'at the start' says to put letters next to each other.
'yards' after 'steel' is 'STEELYARDS'.

Can you help me to learn more?

I've seen this clue in The Guardian.

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