Semicircular kiyi imhando yekiyi, kumusoro kwayo indege, iyo yepasi pasi ndeye semicircular arc, iwo maviri mativi akafanana, anowanzozivikanwa secrescent kiyi.Nzvimbo yekushanda ye semi-denderedzwa kiyi mativi maviri, uye torque inofambiswa nedivi.Iine kusarerekera kwakanaka kwakafanana seflat bond.Kiyi inogona kutenderera nepakati pearc curvature yepasi penzvimbo yegorovha mune shaft groove, saka inogona kujairana nekurerekera kwepasi peiyo hub keyway.