Answer
Saffisni naanneffannaa guddaan $N$ kan gingilchaan alaa shaafta irratti qabannaa dhabu $N = _x000c_rac{1}{R_m} imes ext{√}(_x000c_rac{4 E I g (D_G - D_I)}{w _x000d_ho A R_m^3})$ bakka $E$ moojuulasii ta’etti kennama kan inershiyaa, $D_G$ daayameetira qoochoo, $D_I$ daayameetira keessaa gilgaala, $w$ bal’ina meeshaa, $_x000d_ho$ dhangala’aa, fi $A$ naannoo qaxxaamuraa dha. Shaaftichi akkuma naanneffamuun humni seentirifuugal ulfaatina gilgaala irratti hojjechuun akka babal’atu taasisa. Yoo babal’inni walsimsiisa gidduu seensaa (‘cling’) caale, gingilchaan sun groove keessaa ba’a. Hojiiwwan saffisa guddaa qabaniif, injinaroonni 'Self-Locking' spiral rings ibsu, kunis mala tab-and-slot kan babal'ina makaanikaalatti ittisu qabu.