Making error, fit gear incorrectly into appliance (12)
I believe the answer is:
refrigerator
'appliance' is the definition.
(refrigerator is a kind of appliance)
'making error fit gear incorrectly into' is the wordplay.
'making' is an anagram indicator.
'incorrectly' is an anagram indicator (I've seen this in other clues).
'into' indicates putting letters inside.
'gear' is an anagram of 'gera'.
'error'+'fit'='errorfit'
'errorfit' is an anagram of 'refritor'.
'refritor' going around 'gera' is 'REFRIGERATOR'.
(Other definitions for refrigerator that I've seen before include "Icebox" , "Kitchen appliance" , "Means of storing food" , "Chilled compartment" , "it will freeze!" .)