Tool for cutting around left wheel shaft (4)
I believe the answer is:
axle
'wheel shaft' is the definition.
(I've seen this before)
'tool for cutting around left' is the wordplay.
'tool for cutting' becomes 'axe'.
'around' is an insertion indicator.
'left' becomes 'l' (common abbreviation).
'axe' going around 'l' is 'AXLE'.
(Other definitions for axle that I've seen before include "Shaft on which a wheel rotates" , "Wheel-shaft" , "Rod at centre of wheel" , "Metal pin on which wheel revolves" , "wheel section" .)