Chatter insanely but make steady progress (7)
I believe the answer is:
ratchet
'make steady progress' is the definition.
(I've seen this before)
'chatter insanely' is the wordplay.
'insanely' indicates an anagram.
'chatter' is an anagram of 'RATCHET'.
'but' is the link.
(Other definitions for ratchet that I've seen before include "One-way toothed wheel" , "Bar that fits into the notches of a toothed wheel" , "Mechanical device preventing a wheel slipping backwards" , "Device allowing only one-way motion" , "Set of teeth" .)