A tube positioning apparatus has at least one mandrel for positioning tubes for processing. A variable tube positioning stroke length is facilitated for optimizing stroke length and for optimizing the time required to position and process tube, such as by cutting. The tube positioning apparatus comprises a slide block having a mandrel attached thereto. The slide block is actuated on a plurality of slide rails from a first position to a second position. In the first position, the mandrel is retracted and in a second position the mandrel is extended for access by processing tools, such as circular knives for cutting the tube into desired lengths. A programmable sequence timer is provided for establishing desired time intervals during which the slide block and attached mandrel are in the retracted position or the extended position. In a tube recutter implementation, the programmable timer facilitates selectable time intervals for maintaining the slide block and mandrel in an extended state, engaging cutting means such as circular knives, disengaging the cutting means, and retracting the mandrel from the extended position.