Flush riveting requires that the hole receiving the rivet be countersunk by one of two methods.....dimpling or machining.
Dimpling: Used on material with a thickness less than .040. Dimpling re-shapes the aluminum around the hole, but doesn't remove any material. Dimple Dies are used in the dimpling process and come in specific sizes for the fastener being installed.
Machine Countersinking: Used on material with a thickness of .040 (or greater). To machine countersink, you will use a Threaded Micro Stop Countersink attached to a hand drill/drill press and a Countersink Cutter. The countersink cutters are also size specific to the fastener being used.
Last night, I used the DRDT-2 to dimple the appropriate holes in the Front Spar Doubler and Front Spar. The next step is to rivet the two pieces together. However, I am going to hold off on doing that right now because I first want to epoxy prime the two pieces.
Next, I final drilled the Rudder Attach Holes in the three Hinge Brackets (they are in white in the picture below) to their final size. Then, the Rear Spar, Rear Spar Doubler, and the three Hinge Brackets are all clecoed together.
