7.7.24 – 26 Drill & debur access plates

Now that the fuel tank end ribs have a large hole in them I cleaned up the edges by deburing them and lightly sanding them. I located the stiffener rings and offered them up to the holes. I was really pleased with the fit.

I then marked up the hole locations as I didn’t want the rivets for the nutplates to interfere with the tooling hole. I needed to rotate the stiffener ring slightly to avoid too much interference, but no so much as it would impact the siting of the fuel pickup tube. I finally settled on this which was just enough for edge margins…

Once that was done I fired up the compressor to start drilling when there was an almighty bang! The inline oiler exploded! Doh!

That made this session interesting! I removed what was left of the oiler and replumbed the airline. Now that I have air (!) I was able to get started on drilling the access plate covers.

I repeated that process on the other rib and then marked up all the parts.

By the end of the session the left & right ribs, stiffener rings and access plates were all done.

7.7.23 Cut fuel tank access holes

A little bit blurry following the new years’ celebrations but thought I would have a go at cutting the access holes in the inboard ribs. These holes are used to access the fuel tanks if any work is needed on the fuel pickups or fuel gauge sensors. To tackle this job I needed to use a very dangerous fly cutter. These things have been known to cause serious injury so maximum concentration and precautions needed.

I purchased a hole cutter from Toolstation which had two blades. I decided to remove one of the blades as the chances of having both precisely located enough for them to share the cutting workload was so slim. Instead I decided to use 1 blade for each rib expecting to wear out these blades very very quickly. I also rigged up a piece of plywood underneath the rib on the drill press so that if the fly cutter shot through the aluminium it wouldn’t catch on the steel table of the drill press. I’d read that it was a good idea to really clamp the workpiece down so I did everything I could to make sure it wouldn’t move.

I ran the drill on the slowest possible speed and just scratched away as slowly as possible and with the lightest pressure on the drill arm. Slowly, slowly I made progress and god the rib access hole cut. It was a satisfying feeling to get them both done.

It was a great start to the new year getting this job done. One of the more scary jobs now out of the way.

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