Nima uchun ko'r perchinlar mandrelni buzadi va tortish tirgakning uzilish nuqtasida emas?I

1. Mandraning tortish kuchi barqaror emas, sinish nuqtasi kuchi mandrelning tortish kuchiga juda yaqin yoki issiqlik bilan ishlov berish amalga oshirilmagan va mandrel mo'rt.

2. Perchinlashdan oldin mandrel shikastlangan.

https://www.yukerivet.com/news/the-mandrel-of-the-rivet-has-been-completely-pulled-out-is-it-qualified-to-leave-a-penetrating-hole-in- perchinlangandan so'ng-parchin tanasi/