Layin watsawa ya ɗaukakusurwa karfe hasumiya, kuma babban bangaren yana ɗaukar kwanakarfe lettice hasumiya, wanda shine tsarin tallafi na layin watsawa na sama kuma yana goyan bayan mai sarrafawa da waya ta ƙasa. Yana tabbatar da cewa mai gudanarwa ya cika buƙatun nisa daga ƙasa da abubuwa, kuma yana iya jure wa nauyin mai gudanarwa, waya ta ƙasa da hasumiya kanta, da kuma nauyin waje.Karfe kusurwa, wanda aka fi sani da ƙarfe baƙin ƙarfe, dogon tsiri ne na ƙarfe tare da bangarorin biyu suna yin kusurwoyi dama. Akwai karfen kwana daidai da karfe mara daidaito.Madaidaicin kusurwas suna da faɗi daidai daidai a bangarorin biyu. An bayyana ƙayyadaddun ƙayyadaddun sa a cikin girman mm na faɗin × nisa × kauri. Misali, "∟30×30×3" yana nufin karfen kusurwa daidai gwargwado mai fadin 30 mm da kauri na 3 mm. Hakanan ana iya bayyana shi ta hanyar ƙira, wato, faɗi, cikin santimita, kamar ∟3#. Lambar ƙirar ba ta wakiltar ma'auni na kauri daban-daban a cikin samfurin iri ɗaya, don haka girman girman girman kusurwa da kauri yana buƙatar cika kwangilar kwangila da sauran takaddun don guje wa amfani da lambar samfurin kadai. Ƙayyadaddun ƙayyadaddun ƙayyadaddun nau'i na karfe mai tsayi mai tsayi mai tsayi shine 2 # - 20 #. Ana iya haɗa karfen kusurwa zuwa sassa daban-daban masu ɗaukar damuwa bisa ga buƙatun tsari daban-daban, kuma ana iya amfani da shi azaman ɓangaren haɗawa tsakanin abubuwan.

Ilimin asali da buƙatun fasaha donwatsa layin kwana karfe hasumiyazane-zane ya ƙunshi abubuwa da yawa kamar zaɓin kayan abu, girman ɓangaren, ƙirar haɗin gwiwa, buƙatun gini, da shirye-shiryen zane. Abubuwan da ke cikin zane sun haɗa da zane-zane na gaba ɗaya da zane-zane. Ya kamata a raba zanen tsarin zuwa sassa kamar madaukai, giciye hannuwa, jikin hasumiya, da kafafun hasumiya. A cikin zane-zane na tsari, ban da daidaitattun sassa kamarkusoshi, flanges, clamping faranti, fil fil da washers, duk sassa ya kamata a ƙidaya.