Izikrufu zokuseta, ezikwaziwa ngokuba zizikrufu zegrub, luhlobo lwesibophelelo esisetyenziselwa ukukhusela into enye ngaphakathi okanye ngokuchasene nenye. Ngokungafaniyo neebholiti zemveli kunye nezikrufu, izikrufu zokuseta azinantloko kwaye zidla ngokutsalwa ngokupheleleyo. Ziyilelwe ukuba ziqhutyelwe emngxunyeni ogrunjwe ngaphambili kwaye zihlala zinenqaku okanye ikomityi ekugqibeleni enokuthi icinezele i-shaft okanye enye icandelo, inika ukulingana okuqinileyo, okukhuselekileyo. Kule posi yebhlog, siza kuphonononga imiba ephambili ye-screws eseti, kubandakanya neentlobo zazo, izibonelelo, kunye nezicelo eziqhelekileyo.