Sunday, August 24, 2014

Becoming Unhinged - Big-time Hinge Faux Pas

It started out being a productive day but the forward momentum quickly changed direction as abruptly as a well hit racket ball ricocheting off the far wall and coming straight for the head.

The recently painted aft seat hinges have sufficiently dried enough to be installed onto the F-1237G seat back braces so thought it would be good to complete the seats today … little did I know they would not get completed. The aft F-1237F aft hinges were Clecoed onto the F-1237G seat back braces and then riveted in place.
Securing the F-1237F aft hinge onto the F-1237G seat back brace with Clecos.
Using the pneumatic rivet puller to rivet the F-1237F aft hinge onto the F-1237G seat back brace.
Finished seat back brace assemblies.

After the F-1237F aft hinges were riveted onto the F-1237G seat back braces the long hinge pin previously set aside requires being cut into two 14 1/2" long pieces and four 5 1/2" long pieces. After the hinge pieces are cut and dressed on the Scotch-Brite wheel the last 1” of each hinge pin is bent to 90 degrees. I ended up using a hand hack saw to cut the pins … those pins are hard steel so it took a while. If I were to do it again, I would use the Dremel with a cutoff wheel.
Doing it the hard way … cutting the hinge pins with a hand hack saw.
Using the seaming tool to make a 1" 90 degree bend on each of the six hinge pins.
All six hinge pins cut to size and bent to 90 degrees … ready for instilling the seats into the fuselage.

Before installing the seat backs in the fuselage, the F-1237G seat back brace assembly requires a #52 hole drilled in it so the hinge pin can be safety wired after the brace is attached to the seat back.
Looking closely at the left side of the photo where my finger is pointing to the location of the #52 hole that was drilled for the safety wire that will secure the hinge pin.
Seatback brace assembly mated with a seat back.

The excitement was building … it’s finally time to install the seat back assemblies in the fuselage. The euphoria was short lived. The hinge pins would not go into the hinges. Huston … we have a problem. Looking closely at the problem quickly revealed the error. In my haste last fall to quickly get parts ready for the last good priming weather, I missed performing the step to remove the center two eyelets on the F-1237E hinges. Actually, it was easy to miss because it was not a step in the instructions but a reference in a figure on the prints. My bad.  As one can imagine, I became unhinged for a few moments and had some choice words for myself. But now this opens up a whole can of worms in that I have to figure out a good way to remove the center two eyelets on each of the four hinges without creating more problems. Need to think about this a bit.
The two center eyelets on each of the four F-1237E seat hinges need to be removed to make the hinge look like the drawing.

This is a colossal screw-up on my part! I’ve got a few ideas for a quick easy fix, but want to practice on some scrap material first.