After my update yesterday, jpeters made a funny comment about how this thread reminded him of Bob Villa and "This Old House." I've also heard that it reminds folks of American Chopper, Monster Garage, and others. That got me to thinking about one thing on those shows that really irks me. I hate how one minute they show a guy working on a gas tank or fender or something and the next minute it's finished and installed on the motorcycle. I want to see the details as to
how that piece was built.
Sooooo, I had mentioned that the next little piece I needed to make for the tunnel gun door latch was a simple piece of structure to attach the latch to the door. I thought that I'd give everyone a step by step, detailed version of what it takes to build one little "simple" piece........mistakes and all. Now keep in mind, this is a look into the mind of Gary Austin, so it's not necessarily the "right" way to do it.
There are going to be a lot of pictures for this update (I promise not to get this detailed every time Scott). Sorry if it bores those of you who already know how to do all of this.
Okay, here we go...
To start with, I had formed an idea in my head as to what I needed. Tough to take a picture of that though.
What I started with was a reasonably sized piece of aluminum to work with, and then cut it to the length and width needed for the latch.....
Then I put the piece in it's position and marked where I needed to make the shape of the structure.
The next step was to find something that was the same radius as what needed. The ball socket for the tunnel gun worked perfectly for this......
Then it was off to the belt sander for the shaping......
And then the flap wheel on the die grinder to polish the edges up.....
And here it is, all nice and pretty...........wait a minute......that'll never work! Awww Crap!!! What a stupid mistake. This piece has no upper end. How did I think I was actually going to attach it to the structure? Basically, I just made a duplicate of the latch itself...........
After a few more choice words to myself that weren't exactly rated PG-13, I regrouped and started over. This time with a better game plan.
I started with the trusty ol' posterboard and traced out the piece I just made since I know it's dimensions were correct. I then drew a centerline on it as a reference for further measurements. I have to use different colors for different lines so I don't further confuse myself......
Next, I needed to draw the radius for the upper portion of the structure.....
Then I used a circle template to make a nice transition from the large radius to the straight edges........
Once that was done, then I needed to make another large radius that will be the very top edge of the piece.....
And here it is all cut out. Wait a minute....something doesn't look right.....
There, that looks better. I had forgotten to cut out the center piece. DUH!
Now to transfer that shape onto the metal sheet and then trim the sheet down a bit to make it easier to work with......
The first step was to cut out the lower section. Notice I had drilled two small holes on the corners to make for a small radius when the piece is finished.......
Then over to the bandsaw to cut out the rest of the excess.......
To make it easier for me to make those corners, I put in some relief cuts to help the bandsaw blade stay straight and not try to bend or twist......
You can see that for the inside radius, I needed more relief cuts........
Once that was done, it was back to the belt sander for some rough finishing.......
Oooh, that radius on the sander fits just right. Do you reckon that was planned?
Then the flapper wheel polished the edges up nice and smooth......
Now that the piece was built, it was time to start with the installation. The first step to this process was to clamp it in place and start transferring holes........
Once the holes were drilled, then I had to deburr them all.......
I noticed a slight bend was needed in order for the shape to be right. So, I just clamped on to it with some seaming pliers and leaned on it a little. Nothin' fancy here........
There, that fits about right now..........
I needed to drill two small (#40) holes at the very top of this piece so that I can put a couple of #3 SO (soft) rivets in it later to hold it onto the door structure. These rivets will only be used as holder-downers for when the primary structure is disassmbled. They will have no other purpose in life....
I then needed to taper the ends of the piece so that the Plexiglas transitioned nicely off of it when it's all put together. I used the sanding disc on the die grinder for this. It helps to use some solid lubricant on the sanding disc before starting on the alumunum (bar soap also works well).......
Hang in there, we're almost done.
Next, I used my deburring tool to make some quick countersinks for those #3 SO rivets.......
For the other rivet holes, I used the automatic countersink tool. The thing to do with one of these though, is to set it up by drilling holes in a scrap piece of aluminum that is the same thickness as what you are using and setting and testing the depth of the countersinks by placing a rivet in the holes........
Too deep........
Too shallow.......
There, that looks about right.......
Now that the proper depth is set, it's time to countersink the rest of the holes.......
After that is done, it's ready for primer. Once primed, I clecoed the piece in place while it was still wet. This makes for a good moisture barrier and helps seal between the two pieces of aluminum and the steel structure.......
The first rivets to go in are the #3 SO rivets. I'll be using my hand held rivet squeezer for all of the riveting with this project........
Now that those SO rivets are in place, you can see how they hold the upper end of this piece in place even when the clecos are taken away....
Naturally, we didn't have the correct length of rivet for the remaining holes. So I had to cut every rivet needed to the correct length. Typically, you want the length to be 1 1/2 times the diameter of the hole. The rivet on the here on the left is the shortest one we have on hand. The rivet on the right is the correct length after I cut it (sorry for the poor photo).........
The rivet cutter in action.......
Once you get a couple of rivets you think are right, it's not a bad idea to go ahead and squeeze them in place just to make sure..........
Then you just cut the rest of your rivets and squeeze them into place. The finished result looks good.......
And finally, let's see what it looks like on the airplane........
So there you have it. One "simple" piece of structure built and installed. Total time of completion for this single project.........approximately 2 hours.
Now it's back out there to start working on the striker plate for the latch.
Gary
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I am truely amazed at your talent. I have followed this thread with keen interest. Keep up the good work & thanks for step by step updates. I have learned a lot just keeping up with this. 
