It's employed for sharpening loose tin fragments (8)

I believe the answer is:

oilstone

I'm a little stuck... Click here to teach me more about this clue!

'it's employed for sharpening' is the definition.
I can't judge whether this definition defines the answer.

'loose tin fragments' is the wordplay.
'fragments' is an anagram indicator (the fragments are put back together differently).
'loose'+'tin'='loosetin'
'loosetin' with letters rearranged gives 'OILSTONE'.

Can you help me to learn more?

(Other definitions for oilstone that I've seen before include "Block for sharpening chisels, etc" , "that'll give an edge" , "It could sharpen" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.