The single roler bit is composed of a single cone and a lug matched by a bearing.According to different strata and construction requirements, different cutting struclures can be selected; wear resistant carbide are welded and cemented carbide inserts are inserted on the back of the lug.
Vrtalna naprava poganja gred, ki se vrti in ustvarja pozitivni tlak, tako da vrtalni nastavek lahko udarja, valja in striže kamnino. Z drobljenjem kamnine nastane območje drobilnega obroča. nato z nihanjem gredi razbije srednji steber in razbit steber odnese ven, da nastane luknja.