a table saw includes a table , a saw unit coupled to a substantially inverted u - shaped suspension girder , two supporting devices fixedly fastened to the bottom side of the table to support the suspension girder , and two sliding blocks respectively fastened to the two ends of the suspension girder and respectively coupled to a respective arched guide slot in each of the supporting devices to guide movement of the suspension girder along an arched track to keep the cutting reference point of the saw blade in position so that the saw blade can cut the workpiece accurately .