The invention relates to a tool (59) for the primary shaping of a housing (56) for a sensor (28) which is designed to capture, via a sensing element (35), a physical area (33) that is dependent on a variable (12) to be measured, and to emit an electrical output signal (42) on the basis of the captured physical area (33), comprising: – a mould cavity (66) for receiving a material (68) that moulds the housing (56), and the sensing element (35), and – a box having a wall that bounds the mould cavity (66), wherein at least a part (60 to 64) of the wall that bounds the mould cavity (66) is mounted in a displaceable manner.