7.8.4 & 5 Debur & dimple left wing structure

The replacement blind rivet puller arrived from Amazon today so I thought I’d pop up to the workshop for 5 minutes and quickly change the puller mechanism that I melted yesterday. It didn’t take long and worked a treat. I tested it on an AD-41H rivet and it passed. Good enough to do the tank attach brackets when the time comes.

After that I had a quick read of the next steps in the instructions which said the wing ribs should be deburred and dimpled. So I got the debur tool and started doing some ribs.

1,500 holes later and all the rib and rear spar holes in the left wing were deburred! After that I thought I’d set up the drill with the machine countersink bit and do a couple of holes on the main spar…

I had a weird problem while countersinking. I would set it up exactly so that, with a rivet in the hole, the depth of the rivet is 0.007”. However after a 5 or 10 countersinks in succession the holes would get deeper. Some as deep as 0.014”. Weird. Then it hit me. This tool is so accurate that the hole is getting deeper as the countersink bit heats up! So I decided to let the bit cool for a while and try again, great, it was back to the correct depth. From then on I simply countersunk then tested alternately which kept the bit at the right temperature. Soon both sides of the main spar were done.

Lastly, I decided to dimple all the holes in the ribs and rear spar. For this I broke out the pneumatic squeezer. I know I have a hand squeezer but I prefer the pneumatic for where good ol’ fashioned brute force is called for!

Oops! Five hours gone in the blink of an eye. I guess the lawn mowing will have to wait until tomorrow then! 😂

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