This particular item comprises of a 495 mm stainless steel M8 polished lead screw. The diameter is 8 mm (approx 3/8") with a standard M8 1.25 mm pitch.
This pitch is ideal for small hobby CNC machines, where large speeds are not required, as the fine pitch provides good precision whilst requiring minimal force from a stepper motor, and thus is suitable for direct drive with small stepper motors. Due to the high resolution (0.00625 mm per full step on a standard 1.8 degree motor) vibration is negilgible and a simple drive can be used without microstepping, thus further reducing cost.
The lead screw is supplied polished and has a standard 1.25 mm pitch. There is no machining on the ends except for the face, but 8 mm bore bearings can easily be fitted to either end with standard 8 mm nuts.
This item is shipped by registered international air mail