The hinges for the Vent Door Assemblies are made from Stainless Steel Hinge material. I found that my raw hinge had been cut so as to make it impossible to start a fabricated hinge length from an end. But there was plenty of material to make the required pieces by cutting off ends as required.
The hinges are match drilled using template holes in the vent doors. I clamped them securely as advised, using a vice.
The hinges are very hard, and I found on one of the holes the drill wandered a smidge due to the thinness of the template material.
I had tried to work out a way to clamp and use the pillar drill. In hindsight I would try harder to use a pillar drill for this job.
I clecoed everything to the Firewall to check that the little vent doors moved without fouling the assembly sides.
I found that I needed to remove a very small amount of material from the door edges to ensure a clean movement.
The battery box is an unusual component in that it has been formed from one piece, rather than sides etc being riveted together.
This saves work, but also causes problems …
… it’s harder to debur, and …
… needs some kind of extension to be able to machine countersink the holes.
I used my debur tool handle with the countersink bit screwed in the end.
The bottom row of holes on the vertical side are particularly troublesome due to a flange preventing access, not easily seen in this picture.
I found that with a helper to gently spread the pre-bent sides apart, and deflect the bottom downwards, it was just possible to get the extension into position.
Of course all these countersinks have to be done by eye, with no possible way to get a countersink cage into position.
Anyway, got the job done eventually!