Qhov ci ntsa iab thiab tiaj tus ntawm NO.2B zoo dua li NO.2D.thov dhau los ntawm kev kho tshwj xeeb saum npoo los txhim kho nws cov khoom siv kho tshuab, No.2B tuaj yeem yuav luag txaus siab rau kev siv dav.

Polished nrog txoj siv abrasive ntawm grit # {{{}}

Polished nrog abrasive siv ntawm grit #150-#180, muaj qhov ci zoo dua nrog tsis tu ncua coarse stria, tab sis nyias dua li No.3 yog siv los ua cov tsev da dej sab hauv thiab sab nrauv cov khoom siv hluav taws xob hauv chav ua noj thiab khoom noj khoom haus thiab lwm yam

Polished nrog txoj siv abrasive ntawm grit # {{}}, siv tas li

Cov khoom tau muaj ci ci zoo thiab nyiam reflexivity tuaj yeem ua daim iav

Txias dov ci me ntsis annealed thiab cov tawv nqaij dhau, cov khoom tau ci ci zoo thiab zoo reflexivity zoo li

iav, chav ua noj apparatus, ornament thiab lwm yam