Abstract: Specimen preparation apparatus (10) for preparing a specimen smear on a microscope slide (28) includes a single drive shaft in the form of a horizontal screw (17). A smearer chuck assembly (15) threadably engages the screw whereby rotation of the screw causes, due to friction, rotation of the chuck assembly. Respective stop shafts (21, 22) limit the rotational movement of the chuck assembly and consequently when the assembly bears on one or the other of the stop shafts, continued rotation of the screw causes movement of the assembly axially along the screw. In this manner axial and limited rotational movement of the assembly in either direction is controlled by rotation of the screw in either direction and a smearer blade (19) mounted in the assembly may be moved between a smearing station (27), a rinsing station (30), a cleaning station (31) and a drying station (32).