Improvements relating to shearing machines

A sheep shearing machine including a hand piece with a comb 3 and cutter 4, drive means to cause reciprocal cutting motion between the comb and cutter, and a housing 2 for the hand piece having an outer surface whose shape is appropriate for a user to hold. The shearing machine includes a first portion 10 of the outer surface of the hand piece and a second separate outer portion 7 of the hand piece, the location and shape of the first portion with respect to the remaining portion of the outer surface of the hand piece being such that during conventional use of the hand piece, a portion of the hand of the user can be continuously kept comfortably against some part of the first portion, but that portion of the hand of a user can be voluntarily lifted from this contact at any time during use. The machine also includes means (Fig. 7) responsive to the status of the contact so as to provide a stop signal when the contact is broken and a drive signal while the contact is being maintained.