1. He kūpono ka mīkini no ka hui nui a me ka hana hoʻokahi o ka cylindrical spur a me ka helical gears, worm gears and sprocket.
2. Hōʻikeʻia ka mīkini e ka rigidity maikaʻi, ka ikaika kiʻekiʻe, ka pololei hana kiʻekiʻe, a maʻalahi i ka hana a mālama.
3. ʻAʻole hiki ke hoʻohana ʻia ka mīkini me ka ʻoki ʻana i mua a i hope, akā me ka axial a i ʻole ka radial hānai.