Cov rivets uas muaj lub taub hau countersunk puas xav tau cov qhov countersunk?

Ua ntej siv lub taub hau qhib countersunk rub rivet, nws yog qhov tsim nyog los ua lub qhov countersunk ntawm lub phaj ua ntej, txwv tsis pub nws yuav yooj yim kom tsis sib xws tom qab riveting.