Izikrufu zerola zeplanethi ziguqula intshukumo ejikelezayo ibe yintshukumo yomgama.Iyunithi yokuqhuba i-roller phakathi kwe-screw kunye ne-nut, umehluko omkhulu kunye ne-screws yebhola kukuba iyunithi yokudlulisa umthwalo isebenzisa i-roller ene-threaded endaweni yebhola.Izikrufu ze-roller zeplanethi zineendawo ezininzi zokunxibelelana kwaye zinokumelana nemithwalo emikhulu enesisombululo esiphezulu kakhulu.