Bitewe na helix angle, ingero nyayo yo gukata rake ya kanda iziyongera uko inguni ya helix yiyongera.Ubunararibonye buratubwira: Mugutunganya ibyuma bya ferrous, inguni ya helix igomba kuba nto, muri rusange nka dogere 30, kugirango imbaraga z amenyo yimitsi kandi zifashe kwagura ubuzima bwa robine.Mugutunganya ibyuma bidafite fer nkumuringa, aluminium, magnesium, na zinc, inguni ya helix igomba kuba nini, ishobora kuba nka dogere 45, kandi gukata birakaze, nibyiza gukuramo chip.