Ko te wāhanga tarau o te karu, ina nui ake ko te tarau hinu, he wāhanga takotoranga me te tino whakapēhia ana i roto i te mīhini āhua kōpū. Ko te pōro raro hoki kei reira e noho ana te perekena, ā, ko te kounga o tana hanganga ka whai pā ki te mahi, te maroke, me te roa o te mīhini. Ko te tikanga whakaputa i ngā tarau hinu he tohu anō hoki o te hangarua tata. I ngā poro hiriwiri hiriwiri inaianei, ka hangaia ngā tarau mā te pouri i te poro, kātahi ka whakamahia te tapahi i te pōro. He maha ngā wa o te tapahi, ka timata ki te tapahi paku kia tū ai te nekenga matua, kātahi ka pakari ake, ā, muri iho ka horapa. Ko te horapa te mahi whakamutunga e whiwhi ai i te tāwhai mutunga, te tika o te āhua (te porotaka, te āhua tarau), ā, ko te mea nui rawa, ko te āhua mata me te tauwaewae hohonu e hiahiatia ana kia pai ai te noho o ngā rīhi perekena, te whakapakoko, me te whakahaere i te pātene. Heoi anō hoki te whiringa matā, he nui ngā poro hiriwiri e whakamahi ana i ngā rārā poungao rino, i ngā rārā Nikasil, i te rāpoi pūrere ranei hei whakarato i tētahi mata kore pakaru mō ngā rīhi perekena. I tua atu i te tarau hinu, ko ētahi atu wāhanga tarau matua ko ngā tarau pārahe ki te kapa matua, me whakaputa kia pai te mata kia kumea ai te perekena kia tū ai te pātene mō te pārahe hāpona, me ngā tarau pākihiwi. Ko te hanganga i ēnei wāhanga e here ana ki ngā taputapu CNC māmā, ki te mātauranga roa mō te tribology (te pūtaiao mō te wareware, te huruhuru, me te whakapakoko), me te whakahaere kounga tino, tae atu ki te ine i te mata karearea, me te whakapono i te āhua o te pōro, kia tū ai ngā paerewa tino uaua me te mahi o te ao aunoa.
Kua rite kē te kapa hokohoko mātua ki te āwhina i a koe.