one-side concave diamond grinding wheel for pcb micro drillHigh grinding accuracy; durable; Bond:resin; grinding wheel; OEM. one-side concave diamond grinding wheel for pcb micro drillGrinding hard alloy and other tools;Durable,wide range,less heat,sharp,Passed ISO9001:2000 of CQC,OEM is welcome.ApplicationIt is used for surface grinding semi-atuo peace, diameter as external circular grinding ...