Fuselage Inventory over, I'm back completing the manufacturing of the Flapperons. I have completed the 2 actuation and 4 pivot brackets, made from aluminum stock - Lots of sawing, filing, grinding, polishing and finally priming with Napa 7220 self etching primer from a rattle can. The pieces are laying on the table, waiting to be riveted on the frames.
I drilled the counterweight of the left flapperon which is a 4 feet stainless steel cylinder 1.5 inch diameter hidden under the skin on the photo. The silver clecos sticking up are going through the skin and counterweight holes. Tomorrow I will drill the right flapperon counterweight which is in the background
Notes for the builders: Drill these holes on a drill press. The steel is too hard for a hand drill and the bit will drift and you will end up with ovale holes in the skin. Just mark the holes through the skin, then remove the tube and put it in a vise on the drill press. For deburring the holes in side the cylinder you attach a round file on a dowel or a broom stick and remove as much as you can inside the tube. It does not need to be perfect as it is steel, it will not crack if not perfectly deburred. Even on the drill press there is a risk of drill bit drifting: you need to mark the hole with a sharp punch before drilling. Also do the drilling first with a #40 bit and finish with the #30, this will create smaller burrs easier to scrap from inside.
The photo on the right shows how I tapped the pivot brackets: put the tap bit in the drill press and turn the chuck by hand. You can see that I secured two pivots brackets at a time in the vise so that I need not make the vertical alignment for each bracket. Vertical alignment for both the tap bit and the hole to be tapped is critical so you need a good Drill Press Vise.
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