Abstract: A pair of conveyor belts arranged to form a substantially V-shaped conveying path for slender, elongated tubular members of a predetermined length. A small gap is provided between the conveyor belts at the apex of the V-shaped conveyor assembly. A light transmitter directs a beam across one of the conveyor belts and into the gap toward a receiver. A member to be measured lies in the V-shaped groove periodically breaking the beam according to the length thereof. A pulse generator develops output pulses at a rate determined by the linear speed of the conveyor. First and second detectors count pulses at the initiation and determination of a detector beam to each determine a length. The length of the workpiece is determined by taking an average of the two values.