xov
Lus piav qhia luv luv:
Ib tug kauv zoo li tus nruam convex ib feem nrog ib tug tshwj xeeb seem ua nyob rau saum npoo ntawm ib tug cylindrical los yog conical matrix.Cov xov yog muab faib ua cylindrical threads thiab conical threads raws li lawv niam txiv duab;Nws tuaj yeem muab faib ua cov xov sab nraud thiab cov xov sab hauv raws li nws txoj haujlwm hauv niam txiv lub cev, thiab tuaj yeem muab faib ua cov xov peb sab, cov xov xwm plaub, xov trapezoidal, serrated xov thiab lwm cov xov tshwj xeeb raws li nws cov duab seem (cov hniav zoo nkauj).
