Hoʻokaʻawale ʻia ke apo hoʻopaʻa i loko o kahi apo hoʻopaʻa ʻana i ka lua a me ke apo paʻa paʻa, he hopena palena ʻole a hiki ke pale i nā ʻāpana ʻē aʻe mai ka neʻe ʻana axially.Hoʻohana pinepine ke kaʻina hana i ka punching metala, me kahi ʻāpana hana conical a me kahi "linear contact" ma hope o ka hui ʻana.Hana ʻia kekahi mau hiʻohiʻona nui e ka wili uwea a me ke kuʻi ʻana i nā mea ʻoi aku ka nui, me ka ʻāpana ʻāpana ʻāpana maʻamau a me ka "pili i luna" ma hope o ka hui ʻana.