Assessing the quality of inspection for tapered aircraft fastener holes using an engineer’s blue contact test

Tapered interference-fit fasteners (e.g. Taper-lok) are commonly used by the aerospace industry due to their high fatigue strength. The inspection relies on a ‘true’ geometry gauge coated with a thin film of engineer’s blue being brought firmly into contact with the tapered hole. The pattern created on the gauge is then used to identify bearing surface area and distribution. This research investigates if the inspection reflects the hole...