Brief Description: Final Drill and Dimple Rudder Skin & Substructure
I ordered a drill bit set from Cleaveland (#1 thru #60 in a nice metal box) and it arrived on Friday. Good thing too because I really needed it. Read on to find out why.
The rudder skin and substructure was dimpled today. I used the normal dimples on the skin and the substructure dimples on the stiffeners, ribs and rear spar. All holes were reamed with a #40 reamer before dimpling.
There was a problem trying to dimple the left and right bottom holes on the rear spar flange. My squeezer yolk would not clear the rivet head. If I tried to squeeze the dimple it would have twisted and bent the flange. After thinking about it for a bit I reluctantly decided to drill out the two rivets causing the interference. One of them was the smashed up head I mentioned in an earlier post, so that one had to come out anyway, but the other was perfectly good.
The good rivet came out easily, but I had some significant issues getting the one with the smashed head out. The problem was the head was deformed enough that the rivet removal tool hollow cupped head wouldn't properly center the drill on the fastener hole. I got around this by using a #40 drill to start. It was obvious that the drilled hole wasn't well centered on the rivet head, so I switched to a #35 drill and very carefully used it like an end mill cutter to slowly enlarge the hole. Every so often I'd use my punch to try and pop the head off. Eventually I got it off and I didn't touch the existing bearing surface. That rivet removal tool is rapidly becoming the best $50 I've spent on tools.
Dimpling the rudder skin on the DRDT-2 dimple press.
Middle bottom rivet head interferes with dimpling the flange hole.
