Lub ntsia liaj qhov rooj (lub thauj tog rau nkoj) yog ib tug fastener uas muaj lub taub hau thiab ib tug threaded shank, feem ntau yog siv nyob rau hauv machinery manufacturing thiab kev tsim kho engineering. Nws lub luag haujlwm tseem ceeb yog txhawm rau txuas thiab ruaj ntseg qhov chaw nrog los ntawm qhov los ntawm kev koom nrog cov txiv ntoo, khi rau qhov txuas txuas mus rau lub pob zeb ua ke.
Lub fastener lub ntsiab lub cev muaj ib lub taub hau thiab ib tug threaded shank. Lub shank yog cylindrical thiab muaj cov xov sab nraud, uas yuav tsum dhau los ntawm lub qhov ntawm qhov txuas ua ntej screwing rau hauv cov txiv ntoo. Raws li ib tug derivative ntawm bolts, thauj tog rau nkoj yog feem ntau siv rau anchoring kev sib txuas ntawm steel lug thiab pob zeb hauv paus los txhim kho cov yam ntxwv stability.