Uma kukhulunywa ngokubhola embonini kawoyela negesi, ukukhetha kokubhola kubalulekile ekusebenzeni kahle nokusebenza kahle. Enye yezikhetho ezithandwayo yi-PDC (Polycrystalline Diamond Compact) bit, ikakhulukazi inguqulo engu-8 1/2 intshi enama-blade ama-5. Lolu hlobo lwe-drill bit luhlelwe ukunikeza ukusebenza okuphezulu ezinhlotsheni ezahlukahlukene zokwakheka komhlaba. Ama-PDC bits aziwa ngokuqina nokugqoka