Before revision: Retrieved on 25th February 2014 Technique Overview DHD involves drilling a hole through the thickness of the component, measuring the diameter of the hole, trepanning (cutting a circular slot around the hole) a core of material from around the hole and finally re-measuring the diameter of the hole.A.H.
After revision: Retrieved on 25 February 2014 Technique Overview DHD involves drilling a hole through the thickness of the component, measuring the diameter of the hole, trepanning (cutting a circular slot around the hole) a core of material from around the hole and finally re-measuring the diameter of the hole.A.H.