Kwallan Karfe mashaya, wanda aka fi sani da baƙin ƙarfe na kusurwa, wata tsiri tsiri na karfe ne wanda ke perpendicular ga juna da angular. Akwai kusurwoyi daidai da kusurwoyi marasa daidaituwa. Bangarorin biyu na kusurwoyi masu daidaitawa suna daidai. An bayyana bayanai game da bayanai a cikin milimita na faɗuwar gefe × gefen fadin tabo. Misali, ∟30 x 30 x 3 yana nuna kusan kusurwa ɗaya tare da fadin 30 mm da kauri daga 3 mm. Hakanan za'a iya wakilta shi ta hanyar ƙirar ƙira, wanda shine yawan santimita na gefen, kamar ∟3 #. Misalin bai nuna girman girman kauri daban-daban a cikin samfurin iri ɗaya ba, don haka nisa da sauran takardu sun cika a cikin kwangilar da sauran takardu, don kada a guji yadda ake wakilta shi kaɗai. Hot ya yi birgima daidai-gefen kwana biyu bayani shine 2 # -20 #. M karfe zai iya haɗawa da abubuwan danniya daban-daban gwargwadon buƙatun daban-daban na tsarin, kuma ana iya amfani dashi azaman haɗi tsakanin abubuwan da aka gyara. Ana amfani da shi sosai a cikin tsarin gini da kuma tsarin injiniya daban-daban, kamar manyan bindigogi, hasumiya, hawa da tuddai da hasumiyar masana'antu.