The Collaborative International Dictionary of English v.0.48:

Chafewax \Chafe"wax`\, or Chaffwax \Chaff"wax`\, n. (Eng. Law)
   Formerly a chancery officer who fitted wax for sealing writs
   and other documents.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

CHAFEWAX, Eng, law. An officer in chancery who fits the wax for sealing, to
the writs, commissions and other. instruments then made to be issued out. He
is probably so called because he warms (chaufe) the wax.