Countersunk screws yog tsim rau cov ntawv thov uas ntsia thawv hau tsis pub kom raug, tiam sis sib txuas sib txuas ntawm qhov chaw sib ze yuav tsum ua rau ntawm qhov chaw nrog rau qhov. Ntau yam hauv cov tshuab, cov khoom siv hluav taws xob thiab cov tuam tsev. Tau siv ob qhov sib txuas. Ib qho ntawm qhov chaw yog qhib, thiab lwm qhov yog ua los ntawm ib qho chaw hauv qhov chaw hauv threaded.
Semi-counter-screed screws zoo li countersunk screws, tab sis lawv cov ntawv qhia kheej kheej yog me ntsis raug thiab kuj zoo nkauj thiab du. Feem ntau pom muaj nyob rau hauv cav, khoom siv hluav taws xob, thiab cov vaj tse, thiab lwm yam, nws yog cylindrical thiab muaj concave thiab convex grooves ntawm nws qhov chaw, xws li ib qho chaw ntu uas nyob ib ncig ntawm sab qaum sab nraud, tso cai rau lub hau ntswj rau hau kwv. Qhov loj tshaj plaws sab saum toj kuj tiv thaiv tus screws los ntawm drilling dhau heev los ntawm cov khoom thiab nce lub ntsia hlau siab rau cov khoom. Nws tuaj yeem raug muab tshem tawm lossis rov ua dua tsis txi ntawm kev ua haujlwm, tab sis nws kuj ua kom muaj zog dua thiab rov qab siv tau.
Kev ntsuas kab hluav taws kub taub hau (mm) muaj cov khoom zoo heev, tsis muaj hlau nplaum, kub nyhiab, cov khoom nyhuv, cov khoom siv tib si, muaj kev kub hnyav, muaj zog, ua haujlwm, siv nrog hlau screws, ib co qauv muaj txhav tas. Dav dav siv ntau hom teb.