Knurl, or knurled knob (both k's are silent), slang term, also known as "fine focus" or "spot focus knob" found on Strong Trouper and Super Trouper, and many other manufacturers', followspot s. It is the only ridged or grooved knob on the fixture. Super Trouper II's and long-throw Lycians use a hand knob. Use this adjustment to achieve the desired sharp or soft edge focus.
Old timers may use the phrase, "Work your knurl" which means "adjust your edge" by turning the knob one direction or the other. Akin to "running the barrel" on an ERS.
Old timers may use the phrase, "Work your knurl" which means "adjust your edge" by turning the knob one direction or the other. Akin to "running the barrel" on an ERS.