Spooner's sensible boring task for tool (8)
I believe the answer is:
chainsaw
'spooner's' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I don't see?
'sensible boring task for tool' is the wordplay.
'sensible boring task for' becomes 'chain' (I am not sure about this - if you are sure you should believe this answer much more).
'tool' becomes 'saw' (saw is a kind of tool).
'chain'+'saw'='CHAINSAW'
Can you help me to learn more?
(Other definitions for chainsaw that I've seen before include "woodcutter?" , "Powered cutter" , "Timber cutter" , "powered device" , "Texas massacre tool" .)