Answer
Ƙarfin ƙaddamarwa shine ƙananan dabi'u biyu: Ring Shear da Ƙarƙashin Tsagi. Ana ƙididdige ƙarfin ƙarar zobe kamar $P_r = _x000c_rac{D imes t imes au imes _x0008_eta}{S}$, inda $D$ shine diamita na shaft/bore, $t$ shine kauri na zobe, $\tau$ shine ƙarfin juzu'in kayan zobe, kuma $\beta$ shine yanayin aminci. Nakasar tsagi (samar da ƙasa) yawanci shine ƙayyadaddun abu lokacin da aka yi gidaje da abubuwa masu laushi kamar aluminum. Ana ƙididdige shi bisa zurfin tsagi ($ d$) da ƙarfin yawan amfanin ƙasa ($\sigma_y$): $P_g = _x000c_rac{D imes d imes \sigma_y imes an(\alpha)}{K}$, inda $\alpha$ shine kusurwar lamba. A yawancin ƙirar injiniya, ana amfani da ma'aunin aminci na 2 ko 3 don tabbatar da tsagi baya 'birgima' kuma ya fitar da zoben a ƙarƙashin nauyin nauyi.
