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In January 2011 Perfect Point was contacted regarding an upcoming project to upgrade much of the avionics on a foreign customer C-130, but part of that project was some structural work specifically involving removal of the rainbow fittings attaching the wings to the center wing box (highlighted below).
The rainbow fittings in early C-130 MODELS are attached to skins and stringers using a large number of 3/16” Alloy Steel Taper-Lok fasteners of various grip-lengths (as the rainbow-fitting thins out). Most of these fasteners may be removed, though tediously, by unscrewing the collar and levering the pin out of the skin. However in approximately 10-15% of cases the collar is not accessible or there is insufficient space to lever out the pin after collar removal. In these cases, until e•drill, the only way to remove these fasteners has been to drill them out through most if not all of the grip-length. This task is time-consuming, hard work, has a high damage risk and causes a large amount of FOD.
Prior to involving e•drill, PPedm was provided with a coupon to experiment with, with the intention to determine if the head of Taper-Lok fasteners could be removed in the “forward” direction using e•drill. Conclusions were that e•drill could remove these fasteners by cutting deep inside the pin, severing the head (now with a skirt), then forward punching the pin through the structure.
After successful Proof of Concept (PoC), arrangements were made to rent a system for this project, and arrangements were made for training and on-site support.