support plate 6 and engaging the motor 14 the motor has an output shaft 20 with a driving part 22 such as a gear or the like a preferably internally toothed drive belt 24 drivingly connects that driving part 22 to a driven part 26 on the end of an elongated externally threaded lead screw 28 mounted on the lead screw 28 is an internally threaded nut 30 which when the screw 28 is rotated will move along the screw the nut 30 is connected by structure generally designated 32 to the moveable table part 4 so that the two will move together the lead screw 28 is rotatably mounted on the support plate 6 with one end thereof to which the driven part 26 is connected passing through a hole 34 in the support plate 6 the lead screw 28 as here specifically disclosed is mounted in cantilever fashion on the support plate 6 by the front end retainer 36 secured to the support plate 6 by screws 38 passing through holes 40 in the support plate 6 and threaded in holes 42 in the front end tube support 36 which includes forwardly extending cylindrical portion 36 a received within the front end tube support portion 36 a are a pair of ball bearings 44 and 46 which support the right hand end of the lead screw 28 the lead screw 28 extends through an elongated tube 48 the right hand end of which extends over the cylindrical portion 36 a of the front end tube support 36 and is there held in place by the locking.