Got to work on the practice kit and do some actual drilling, dimpling and riveting. My first rivets ever. Got every thing deburred and cleco'd the ends on the box, and then immediately made a big mistake. The ends are supposed to be 3/32" (-3) rivets - that registered clearly in my head that those are the smaller rivets and I instinctively grabbed the #30 drill bit. After match drilling half the holes on both ends, I moved the 3/32 clecos over and immediately knew I screwed up. #30 bit is for the 1/8" (-4) rivets. Oh well, that's why it's a practice kit. I just proceeded to drill them all to #30 and used the AN426-4 flush rivets that were provided with the kit. If it were the actual airplane I would have stopped and at least checked the edge clearances for the larger rivets.
My DRDT-2 isn't here yet so I used the squeezer to dimple to the box and the ends. Piece of cake. Then re-cleco'd and started driving flush rivets with the squeezer. That squeezer is way too easy; pretty much all perfect right off the bat. The squeezer won't reach the line of rivets across the bottom so I used the gun and the tungsten bar. Still pretty easy because I had the bottom of the box to rest the bar against and keep it square. Most turned out pretty good and no damage to the skins; I used blue painters tape on the flush set, but also did some without it and really didn't note any difference.
The rivets along the front edge of the box are AN470's with the button head. I used the squeezer on the first few. Again, couldn't be easier so I moved over the gun and bucking bar for the rest. This time I didn't have anything to support the bar against so it was a little more challenging. I got my first smiley too. Then another.
The most challenging rivets were the for AN470's on top that hold the handle. The box top is an awkward shape and hard to support while driving with the gun and bar. All four turned out bad. Got good practice drilling them out. Second attempt a little better, but still drilled out two of them. Third attempt was passable, but still probably the worst of the rivets I did today. Following the recommendation of other builders, I'll probably drill out all of the rivets and redo them just for the practice. Ordered some extra rivets from Aircraftspruce, including the replacements for the -4's I borrowed for the end skins. I can see a lot of time in my future waiting on parts or tools.
I also worked on a rib flange bender this week and finished it this morning. I know I don't need this for a while, if at all, but I saw it on the forums and realized I had most of the parts. I was just itching to fabricate something with all of my new tools. Came out pretty nice; can't wait to use it.
Lessons Learned:
- read the notes, slow down, read it again, before you drill, read it again, before you dimple, make sure it's the right side
- Use the squeezer whenever possible
- Running the rivet gun at about 50psi on the regulator. After setting the regulator, run the gun, then set it again. The pressure drops significantly after the first use of the tools.
- My 18v electric drill seems to run higher rpm than the air drill - might need to increase the pressure on the drill. I was running it at 90psi. Electric drill is definitely an option.
- Find a way to support the work when using the gun. It will move around on you.
- Instinct is to put a cleco in the corner of a plate. When doing this the first rivet is away from the corner and tends to curl the plate up. Better to cleco the second hole so that the first actual rivet goes in the corner.
- This is going to be fun. I'm really enjoying having a metal shop.
Purchases: HF airhoses & accessories, ACS Rivets