Factory I came across dealing with small measure (10)

I believe the answer is:

millimetre

'small measure' is the definition.
(small measurement)

'factory i came across dealing with' is the wordplay.
'factory' becomes 'mill' (synonyms).
'came across' becomes 'met' ('meet' can be a synonym of 'come across').
'dealing with' becomes 're' (regarding).
'mill'+'i'+'met'+'re'='MILLIMETRE'

I've seen this clue in The Times.

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