captainron
Well Known Member
OK, I know I'm going to catch much grief over this, but maybe one of the experts like Dan or Mel can answer this. I assembled my RV-7 empenage at Alexander Tech Center, which was a great experience and I highly recommend them. However, I just don't get the whole match-drilling thing. The assembly would be cleco-ed together and then reamed with a #41 reamer, which by the way I think is better than using a #40, giving more support to the rivet.
I never saw a hole that didn't line up, but I did notice that when I occasionally became lazy and spaced the clecos too far apart, I might get an enlarged hole in the underlying piece.
When this happens, it seems to defeat the idea of matched holes.
Next, the assembly is taken apart to be dimpled, de-burred, prepped, etc..
You can't tell me that dimpling, deburring, running clecos in and out doesn't change dimensions slightly.
The prepunched holes already fit over the dimple pin without any drilling or reaming, which means you can drop a rivet right into the dimpled hole.
To quote Van's directly: "In the "matched hole" RV-7/7A kit, a computerized punch press locates and punches all the rivet holes during manufacture, so the builder can pull the parts out of the box, align the holes and begin assembly immediately."
I was begining to think that the whole "match-drilling" thing (or even reaming at all!) is a colossal waste of time and introduced more errors into the work. I decided to do one elevator the "approved " way, and on the other, simply ream all holes seperately, dimple and prep normally and rivet together.
The end result were two perfect elevators, but with the knowledge that one of them had perfect holes that weren't match-drilled. And, much less time invested in re-doing what you've already paid Vans for.
Comments?
I never saw a hole that didn't line up, but I did notice that when I occasionally became lazy and spaced the clecos too far apart, I might get an enlarged hole in the underlying piece.
When this happens, it seems to defeat the idea of matched holes.
Next, the assembly is taken apart to be dimpled, de-burred, prepped, etc..
You can't tell me that dimpling, deburring, running clecos in and out doesn't change dimensions slightly.
The prepunched holes already fit over the dimple pin without any drilling or reaming, which means you can drop a rivet right into the dimpled hole.
To quote Van's directly: "In the "matched hole" RV-7/7A kit, a computerized punch press locates and punches all the rivet holes during manufacture, so the builder can pull the parts out of the box, align the holes and begin assembly immediately."
I was begining to think that the whole "match-drilling" thing (or even reaming at all!) is a colossal waste of time and introduced more errors into the work. I decided to do one elevator the "approved " way, and on the other, simply ream all holes seperately, dimple and prep normally and rivet together.
The end result were two perfect elevators, but with the knowledge that one of them had perfect holes that weren't match-drilled. And, much less time invested in re-doing what you've already paid Vans for.
Comments?