This is Octagon’s latest development in Precision Screw Diameter Measuring Machine originally designed by National Physical Laboratory (NPL)- UK in 1940s. For enhancing the accuracies of the old design, Octagon has redesigned this machine with integration of the latest technologies of 21st Century and complying to the NPL specifications of MOY / SCMI/9 ( issue 7) 2001. This measuring machine is specially designed for precision measurement of screw thread gauges and cylindrical shafts. In this machine design, the measuring axis is constantly held at the right angles to the axis of the centers. This design allows precision measurement of screw threads by two wire method. The component being measured is mounted between a pair of centers and the measuring carriage float freely in the right-angle to the axis of the centers, facilitates most accurate diametrical measurements. The measuring spindle is precisely guided in the measuring carriage and is maintained in the axis of the centers to ensure compliance with Abbe’s Principle.