Large heat developed in machine (5)
I believe the answer is:
lathe
'machine' is the definition.
(I've seen this before)
'large heat developed in' is the wordplay.
'large' becomes 'l' (**).
'developed' indicates an anagram.
'in' is an insertion indicator.
'heat' with letters rearranged gives 'athe'.
'l' inserted within 'athe' is 'LATHE'.
(Other definitions for lathe that I've seen before include "Wood-shaping machine" , "Turning instrument" , "piece of machinery" , "Turning tool" , "8 [TURNER]" .)