A cikin ayyukan ginin ƙarfe da rufin ƙarfe, ana sa ran screws za su shiga cikin farantin ƙarfe da kyau ba tare da an riga an yi hakowa ba. Dangane da ka'idodin gwajin JIS, ana kimanta aikin hakowa bisa kaurin faranti, lokacin hakowa, matsakaicin nauyi, da saurin juyawa.
Gwaje-gwajen masana'antu na baya-bayan nan sun nuna cewa zaɓin maƙasudin rawar soja ba daidai ba yakan haifar da wuce gona da iri na lokacin hakowa, zafi fiye da kima, da lalacewa na kayan aiki da wuri. Wannan ba wai kawai yana rinjayar ingancin shigarwa ba amma yana ƙara haɗarin fashewar tip yayin babban ƙarar ƙarar-.
Bayanan tunani na JIS yana nuna a sarari cewa girman dunƙule daban-daban da wuraren rawar soja an tsara su don takamaiman jeri na kauri na ƙarfe. Misali, zanen karfen bakin karfe yana buƙatar saurin hakowa da tsayayyen shigarsa, yayin da faranti masu kauri na ƙarfe suna buƙatar ƙarfafa tukwici da kuma sarrafa RPM don kiyaye kwanciyar hankali.
Ga masana'antun da ƴan kwangila masu hidima ga kasuwar Kudancin Amurka, fahimtar waɗannan ƙa'idodin yana taimakawa rage gazawar shigarwa da haɓaka ingancin aikin gabaɗaya. Yayin da tsarin ƙarfe da tsarin rufi ke ci gaba da haɓakawa, bin ƙa'idodin gwajin da aka sani yana ƙara zama mahimmanci.
