The tool the fellow took up: a rake (4,3)
I believe the answer is:
fret saw
'a rake' is the definition.
Both the definition and answer are singular nouns.
Maybe there's an association between them I don't understand?
'the tool the fellow took up' is the wordplay.
'the tool the fellow' becomes 'fret' (I can't explain this - if you can you should believe this answer much more).
'took' becomes 'was' (being is a kind of taking).
'up' is a reversal indicator (in down clue: letters go upwards).
'was' backwards is 'saw'.
'fret'+'saw'='FRET SAW'
Can you help me to learn more?
(Other definitions for fret saw that I've seen before include "Cutter for wood/metal" , "Fine-toothed tool with a narrow blade" , "Narrow-bladed cutter" , "Cutter for thin wood" , "Tool for cutting designs in wood" .)