Abstract: A painter shaker having a base housing with a double acting pneumatic piston and cylinder motor horizontally mounted within said housing. The motor includes a cylinder and a reciprocable piston in the cylinder having a piston rod slidably and sealably extending through one end wall of said cylinder. A clamp mechanism for holding a container to be shaken is secured to a vertical shaft rotatably mounted on said housing for oscillation about a vertical axis. A crank arm connects the vertical shaft to the piston rod. A disc type bistable control valve is mounted transversely directly on the lower side of the air cylinder. The bistable valve includes outlet ports communicating with inlet ports on the cylinder at the rod end and compressed air is supplied to said valve through a check valve, the control disc controlling the flow of air to the outlet ports.