Xov yog ib hom ntawm qhov chaw cov khoom los yog puab nplaim tus ntoo khaub lig seem, yog muaj ib yam muab kauv convex. Thiab ntsia hlau fastening txhais uas ceev ceev ntawm tus ntsia thawv threads ntawm lwm cov teeb. Chav kawm ntawv hais txog cov ua ke nrog nrog thiab lwm cov sib txawv thiab kam rau ua.
Rau xov, xov qib muaj cov nram qab no 3: 1A, 2A, 3A. Cov qib ntawm sab hauv xov muaj cov nram qab no 3: 2B, 3B, 1B, tag nrho cov muaj tus kis, ntau dua qhov kev lawm, qhov ntau seem txeej. Xov, qhov sib txawv ntawm 3A tiaj 0, 1A thiab 2A yog sib npaug.
Tus 1A thiab 1B yog xoob heev kam rau ua ntau ntau, tsis tsim rau siv lwm xov thiab cov kam rau ua ntawm sab hauv xov. 2a thiab 2b yog imperial fasteners txhua yam rau qib kam rau ua xwb; Qeb 3b 3A thiab cov, yuav saws synthesis, tus haum nruj, feem ntau siv tighter tolerances rau fasteners, thiab muaj kev ruaj ntseg tseem ceeb tsim.
Cov kam rau ua tshwm sim ntawm cov theem 1A thiab 2A sim lwm xov, 3A tsis kawm. Feem ntau, 1A sim kam rau ua tseem loj tshaj 2A hoob 50%, ntau dua Qib 3A 75%. Sab hauv threads ntawm 2B qib uas kam rau ua yog 30% loj tshaj 2A hoob kawm. 1B theem muaj 50% ntau dua 2B hoob kawm, 75% loj tshaj 3B hoob kawm.
