3.8 Hours -
I woke up today with the goal of smashing some rivets. For me, getting to a step where some rivets go in would feel like a huge accomplishment. Plus, I wanted to see how well the pneumatic squeezer worked on some 4- rivets. Yes, I’m one of those people that loves the little things in life!
My work was broken up into two shifts. Unfortunately, I had non-airplane related stuff that had to get done too.
In the morning, I started by cleaning and priming all the HS ribs. Once the primer was on, I moved over to the HS skins and started to deburr the holes and edges. This was a time consuming process and I only managed to deburr the holes in one skin before I decided it was time to break for lunch and go get my other stuff done.
The HS ribs are primed and ready for assembly.
More tedium...deburring the HS skin drill holes.
In the afternoon, I returned to my HS skin deburring task. It probably took me another hour to finish the holes and edges of both skins.
Using a dove-tail deburring tool to break the edges of the skins.
Using a swivel style deburring tool in the tough to reach areas.
After deburring the HS skins, I began dimpling all the holes. I dimpled as many holes as I could with my pneumatic squeezer and then switched to a c-frame dimpler.
This was the first time I used my c-frame. Fortunately, I checked it’s alignment before whacking away on it with a hammer. The bottom plate, which held my male dimple die, was slightly out of alignment. If I would have used it this way, it likely would have dimpled fine. However, it would have put a lot of stress on my die, eventually causing the male die to break (ouch!). Fixing the alignment was simple, and it actually took me longer to find the right sized Allen wrench than it did to get everything into alignment.
Once the c-frame was set-up, I slid one of the HS skins in and started to dimple the easy to reach holes. After a few holes, I realized I either needed another hand or I needed to build some sort of dimpling table. It was difficult to hold these large skins thanks to the bend they have. I couldn’t find an easy way to hold the skin on the die, hold the bend open enough to allow space for the hammer, and swing the hammer with enough force to get a good dimple. This was starting to frustrate me and my goal for the day was to set some rivets, so I sat the HS skins aside and reassembled the HS rear spar for riveting. Maybe holding the skin sideways will simplify this…skins without bends should be much easier.
I dug out the two HS-603PP rear spar channels and the two HS-609PP rear spar reinforcement bars. After figuring out the correct orientation (my markings weren’t very helpful), I clecoed them together. As per the instructions, I taped over the holes that will be used to attach the ribs so that I wouldn’t accidentally rivet them. I also re-attached the elevator attachment brackets so that I wouldn’t rivet those with the wrong sized rivets.
With everything clamped together and marked, I was ready to smash some AN470A4-6 rivets! I grabbed a rivet from the bin and tried to place it in the center hole on the bottom of the spar. It wouldn’t go all the way through both pieces. After double checking that I had the right rivet size, I took a close look at the rear spar. Even though the channels and reinforcements were clecoed together on every other hole, the holes were slightly off and not perfectly aligned. At first, I wondered if I had oriented the reinforcement piece the wrong way, but I quickly determined that was not the case. Before getting too frustrated, I realized that the clecoes are smaller than the actual holes and could be the source of my problem. So, I removed all the clecoes from the lower reinforcement piece and placed rivets in the holes instead. Using this method, everything lined up perfectly. Relieved that I hadn’t made a major screw-up, I removed every third rivet and put the clecoes back in those holes in order to keep the pieces tightly clamped for riveting.
Finally, it was time to rivet! Setting up the squeezer on the first rivet was surprisingly simple. After a couple of progressively shorter squeezes, my rivet gauge said I had the appropriate sized shop head. With the squeezer set-up, I proceeded down the rivet line, checking every two or three rivets with the rivet gauge to make sure the squeezer was still set-up correctly. The entire row of rivets took about 15 minutes. I’m guessing that the same number of rivets would have taken me about an hour with a hand squeezer (if I didn’t get tired and quit half way through). I left the second row for another day…dinner time!
A perfect shop head according to my rivet gauge.
Riveting using the pneumatic squeezer yields more consistent results.
