Igrit yentsimbi engenasiciyintsimbi engatyiwayo ngamasuntswana angama-angular.Ubukhulu becala isetyenziselwa ukucoca umphezulu, ukususwa kwepeyinti kunye nokwehla kweentsimbi ezingezizo i-ferrous kunye neemveliso zetsimbi engatyiwa, zenza uburhabaxa obufanayo bomphezulu, ngaloo ndlela bufaneleke ngakumbi ukunyangwa komphezulu ngaphambi kokugquma.