Tag: joggle

April 22, 2015 – Well to start with, the dates on the next few posts are skewed, because I haven’t had internet access at home for a week. It’s a good thing I have this project because I would have gone totally nuts…

I kept  good track of my time, but I’m writing all these posts on the same day…

So I drilled the floor stiffeners. The outboard ones were a non-event. Not really even any pictures.

I then clamped the inboard stiffeners in place. I quickly realized I might have a problem because I had drawn a centerline on top of the stiffeners, and couldn’t get that line to appear through the holes in the skin. Yes, I’m sure they were in the correct location, and left and right were correct.

I decided to go for it and drill them to see where I stood. Here they are clamped in place, and then drilled:

Here they are from underneath:

I had minimal edge distance for the holes to the edge of the angles. Strictly speaking, it was legal, but I didn’t like it. Here’s an angle out on the table:

I decided to replace the angles with 1″ flanges instead of the 3/4″ angles provided. I found the same angles at Aircraft Spruce.

I knew when I was ordering them that I’d have to decide how to fit them, because the originals are joggled to fit over the firewall angle and the F704 bulkhead flange. I decided to attempt to joggle them.

I cut them to length, and had about an 8″ piece of scrap off each one. I tested my joggles on those scraps. Here’s how I did it:

A quick lesson in joggles:

Since the angle fits over a flange on the firewall that’s .125″ (1/8″) high, I used 1/8″ scrap to do the bends. I found two pieces of scrap, and rounded the edges that would contact the angles, in order to prevent scarring the metal.

I taped the pieces on opposite sides of the angle flange to be bent.

Then  I placed the whole thing in the vise. After a couple of tests where I really tightened the vise hard, I realized I didn’t have to try that hard; just making it snug did the trick.

And here’s the joggle. It’s at least as good as they come from Van’s:

Back to our story:

Now I could get back on track. I clamped the angles in place. You have to notch the forward ends to allow clearance around one of the angles on the firewall.

I drilled the angles through the skin, then drilled through the angles at the forward and aft ends.

Now, I haven’t figured out what the original problem was with the fit, but I think the heavy angles on the firewall are off by a hair, because when I unclamped the stiffeners, they sprung out a little bit.

I decided just to shim the stiffeners at these angles.

Time: 6:20