Rack and Worm Gears Small 222×320 Medium 444×640 Large 710×1024 Download Tiff Original 1664×2400 | (767.6 KB) Description A gear system with a rack gear and worm gear. Used to conovert circular motion to rectilinear motion. Keywords Galleries Gears Source: William Dwight Whitney The Century Dictionary and Cyclopedia: An encyclopedic Lexicon of the English Language (New York, NY: The Century Co., 1889)