Nsonga ziwirizida za nyongolotsi ndipo gudumu la nyongolotsi ndi mtundu wa makina a zida zomwe zimagwiritsidwa ntchito potumiza mphamvu. Lili ndi nyongolotsi, yomwe ndi gawo lozungulira lofanana ndi sikurufu yokhala ndi mano ozungulira, ndi gudumu la nyongolotsi, lomwe ndi giya yokhala ndi mano omwe amalumikizana ndi nyongolotsi.
Mawu akuti dual lead amatanthauza kuti nyongolotsi ili ndi mano awiri, kapena ulusi, womwe umazungulira silinda pamakona osiyanasiyana. Kapangidwe kameneka kamapereka chiŵerengero cha giya chapamwamba poyerekeza ndi nyongolotsi imodzi ya lead, zomwe zikutanthauza kuti gudumu la nyongolotsi lidzazungulira kangapo pa kuzungulira kwa nyongolotsi.
Ubwino wogwiritsa ntchito gudumu la worm ndi mphutsi ziwiri ndikuti limatha kupeza chiŵerengero chachikulu cha giya mu kapangidwe kakang'ono, zomwe zimapangitsa kuti likhale lothandiza pa ntchito zomwe malo ndi ochepa. Limadzitsekera lokha, zomwe zikutanthauza kuti mphutsi imatha kugwira gudumu la worm popanda kufunikira brake kapena njira ina yotsekera.
Makina awiri a mphutsi ndi mawilo a mphutsi amagwiritsidwa ntchito kwambiri pamakina ndi zida monga makina onyamulira katundu, zida zonyamulira katundu, ndi zida zamakina.