7PC SOCKET CAP SCREW COUNTERBORES M3 - M12. STANDARD COUNTER BORE SIZES FOR METRIC CAP HEADS.M3, M4, M5, M6, M8, M10 & M12. The item "7PC SOCKET CAP HEAD SCREW COUNTER BORES COUNTERBORE SET" is in sale since Monday, August 22, 2011. This item is in the category "Business, Office & Industrial\CNC, Metalworking & Manufacturing\Metalworking Equipment\Other Metalworking Equipment". The seller is "rdg355" and is located in YORKSHIRE. This item can be shipped worldwide.