Tool useful for cracking some walnuts (3)

I believe the answer is:

awl

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'tool' is the definition.
(I know that awl is a type of hand tool)

I cannot understand how the rest of the clue works.

(Other definitions for awl that I've seen before include "Borer, sounds like everything" , "scribe" , "Tool for piercing holes in leather" , "What could be boring" , "Pointed tool used in leatherwork" .)

I've seen this clue in the Evening Standard.

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