Counterbore Hole Size for Shoulder Screw (ISO)

A counterbored hole is usually used for when the top of a screw or bolt needs to be flush with, or sit just beneath, the surface of the material it is inserting. For example, a shoulder screw with a counterbored hole sits flush with the surface, whereas the shoulder screw with a simple clearance hole…

Countersunk Hole Size for Socket Flat Head (ANSI Inch)

Unsure on what size countersunk hole to use for your ANSI Inch socket flat head fasteners? Use the image and chart below to determine what dimensions to use, all dimensions are in inches apart from the countersink angle. For example, an ANSI Inch 1/2″ flat head screw with a normal fit countersunk hole will require a…

Countersunk Hole Size for Flat Head Screws (ISO)

Unsure on what size countersunk hole to use for your ISO flat head fasteners? Use the image and chart below to determine what dimensions to use, all dimensions are in millimeters apart from the countersink angle. For example, an ISO M10 flat head screw with a normal fit countersunk hole will require a pilot hole diameter…

Countersunk Hole Size for Socket Flat Head (ANSI Metric)

Unsure on what size countersunk hole to use for your ANSI Metric socket flat head fasteners? Use the image and chart below to determine what dimensions to use, all dimensions are in millimeters apart from the countersink angle. For example, an ANSI Metric M6 flat head screw with a normal fit countersunk hole will require a…