Tig, raws li cov txheej txheem hlau feem ntau, yog siv dav hauv kev tsim cov tshuab tsim khoom. Nws yog tsuas yog siv rau kev ua rotationally symmetrical hlau qhov chaw, xws li shafts, zog, threads, thiab lwm yam. Cov txheej txheem tig yog nyuaj, tab sis los ntawm tsim nyog desi ...
Nyeem ntxiv