Countersinking

Expectations When Requesting Countersinking 

When countersinking has been requested as a process we would require the following quality criteria:

• Flushness: The primary function of a countersunk hole is to allow the screw head to sit perfectly flush with (or slightly below) the surface of the component. 

• Coaxiality (Concentricity): The center axis of the conical countersink must be concentric with the center axis of the pilot hole beneath it. Misalignment can cause the fastener to sit crookedly, applying uneven stress.

• Burrs and Finish: The countersink should be free of burrs or sharp edges that could interfere with assembly or cause stress concentrations.

• Visual Appearance: The countersink should be smooth and round and show no deformity in it's shape, it should also be centrally located around the hole. 

Please pay particular attention to the location or orientation of the countersink hole. One of the most common errors for countersink holes is that it has been carried out on the wrong side of the material or in the wrong location.

Not Acceptable

Acceptable