Je, sweta ya rivet yenye upofu inamaanisha nini?

Kichwa cha kuruka cha rivet kipofu: kwa sababu rivet haifungi kichwa cha msumari, itasababisha kichwa cha kuruka cha rivet.

https://www.yukerivet.com/news/the-core-of-the-blind-rivet-is-not-completely-pulled-out-what-is-the-reason-for-the-fracture/