Shaped end of wood then too sharp (2,3,3)
I believe the answer is:
on the dot
'sharp' is the definition.
(both can mean promptly)
'shaped end of wood then too' is the wordplay.
'shaped' indicates an anagram.
'end of' suggests the final letters.
The last letter of 'wood' is 'd'.
'd'+'then'+'too'='dthentoo'
'dthentoo' anagrammed gives 'ON THE DOT'.
(Other definitions for on the dot that I've seen before include "At exactly the right time" , "Precisely punctual" , "on precise place in line?" , "Prompt" , "Promptly" .)