Ingabe ama-countersunk head rivets adinga izimbobo ezishisiwe?

Ngaphambi kokusebenzisa i-countersunk evulekile yekhanda idonsa i-rivet, kuyadingeka ukwenza imbobo ye-countersunk epulatifeni kuqala, ngaphandle kwalokho kuyoba lula ukungalingani ngemva kwe-riveting.