THREADING USER GUIDE Tool Types Standard C#-SER/L HSK-SEL U-Type ISCAR GROOVE-TURN TOOLS PENTACUT Carrying Inserts with 5 Threading Corners. For tool information, refer to the section on GROOVE-TURN. Boring Bars Standard E-SIR-HEAD U-Type GROOVE-TURN Boring Bars CHAMGROOVE Holder and Carbide Bar CHAMGROOVE Integral PICCOCUT Holders and Carbide Bars 699