An apparatus for applying a force to a specimen is provided. The apparatus comprises: an output rotatable member comprising a plurality of connection points; a plurality of rigid connection means, each comprising a first end and a second end, wherein the first end of each connection means is pivotably coupled to one of the plurality of connection points of the output rotatable member; a plurality of guide members; and a plurality of specimen holders, each slidably mounted to one of the guide members and pivotably coupled to the second end of one of the plurality of connection means.