Special case to carry the blade (6)
I believe the answer is:
scythe
'blade' is the definition.
(I've seen this before)
'special case to carry the' is the wordplay.
'special' becomes 's' (common abbreviation as in Special Air Service).
'case to' suggests removing the centre (the external letters form the word's case).
'carry' with its centre taken out is 'cy'.
's'+'cy'+'the'='SCYTHE'
(Other definitions for scythe that I've seen before include "Long-handled tool for cutting grass or grain" , "Reaping implement" , "One cuts" , "Edge tool" , "Old hay cutter with long handle and curved blande" .)