It takes time to deburr the ribs and stiffeners. Partly it's learning techniques, going over the pieces several times until they are consistent. Partly it's summer. But this marks about a year on the project. Maybe pick up the pace a little?

Before deburring I needed to form some new pieces to replace defectives. Mostly cracks created when pressing the lightening hole flanges. Now I realize I should have deburred/smoothed the lightening holes before pressing the flanges. The fly cutter did leave some roughness. Smoothing before pressing the flanges would have stopped the cracks.

Probably a point in favor of the router method of cutting lightening holes, since the router cuts more smoothly. But the fly-cutter method has certain advantages. At any rate, other builders would be wise to smooth their lightening hole edges before flanging since the metal gets stretched when pressing the flange.

Also, part of the process of prepping these pieces was to check and fine-tune the flanges to 90 degrees and tweaking for maximum flatness/straightness. It occurred to me that if I have to bend things to make them fit upon assembly, then I might be inducing or storing stresses in the structure. Better to minimize that sort of thing by making the pieces as straight as possible to begin with.

Not satisfied with deburring tools. They create a beveled edge on drilled holes if enough pressure is applied to remove the burr. That amount of pressure would also cause the tool to sometimes catch and create a little nick. So I adopted the strategy of going over the pieces lightly, with just enough pressure to remove some of the burr bot not enough to cause a bevel or a nick.

The real deburring was done by Scotchbrite wheel, a few different grades of Scotchbrite pads and 320 grit sandpaper. The Scotchbrite wheel works fast with little effort. Even some of the lightening hole edges are reachable by the wheel. But the bench grinder needs to be respected since it can grab your piece from you and throw it across the shop. Getting close to edges and into tight areas I used a small rotary tool and Dremel wheels, and also cut Scotchbrite pads to fit onto a hand-drilll mandrel.

My EAA Technical Counselor paid a visit and said it was good, though he found a few tiny lips and curls to be smoothed. A fingernail will find the burr where a fingertip will not. The noses of the nose ribs will be removed, and the fore/aft edges of ribs will be cut to length upon assembly, so those edges are not smoothed.

After this, the next steps will be: clean with soap to degrease - etch with Ekoetch - light coat with Ekoprime.

Youtube video to show progress:
https://www.youtube.com/watch?v=uFzPv1zLK2A