a reciprocating laboratory shaker with multiple force cancellations to reduce vibration and noise while permitting , typically , oscillations ranging to ¾ ″ peak - to - peak at speeds ranging to 6000 cpm with sample loads ranging to one pound for shaking durations ranging to at least five minutes , so as to liquify and break down cells in mixtures of biological samples and ceramic beads . the shaker has a frame ; a motor with a double - ended shaft ; a statically - and dynamically - balanced crankshaft at each shaft end , the two crankshafts having 180 ° phase difference ; and two pistons , each of which is constrained for linearly reciprocating movement and connected by an associated linkage to an associated crankshaft . engagement features on each piston engage and retain diverse jig fixtures holding samples for shaking . a jig fixture has a grid array holder holding sample containers , a box holding the array holder , and a space frame , which may be integrated with the box , holding and clamping shut the box while mounting to the piston .