3. Tirnoq boshi tushadi: Perchinlangandan so'ng, mandrel boshini o'rash mumkin emas va perchin tanasidan tushadi.
4. Perchin tanasining yorilishi: Perchinni tortib olgandan so'ng, perchin tanasi uzunlamasına yorilishga ega yoki butunlay yorilib ketgan.
https://www.yukerivet.com/news/the-nail-cap-came-off-what-is-the-reason/
Xabar vaqti: 28-iyul-2022