Crayford Focuser

grabcad

A precise replica of a standard crayford focuser, designed for educational purposes and highlighting the essential components necessary for normal and fine focusing within an astronomical telescope. By rotating a shaft that smoothly interfaces with a flat surface through frictional contact, normal focusing is efficiently achieved, accompanied by minimal backlash. Meanwhile, fine focusing is enabled by a sophisticated planetary gear system, comprising a small central shaft (the Sun) and three larger ball bearings (the Planets), which rotate within a housing (Inner Gear). This intricate setup yields a typical reduction ratio of 1:11. The model was meticulously crafted in Fusion360, a powerful CAD software that incorporates motion links to facilitate the visualization of movement. If you require access to this file, please do not hesitate to send me a message.