I was nervous to do this step: using the corner gouge to cut a feather edge on each corner. If you mess it up both your block and rib can end up in the trash. I waited to do it with Juan's supervision instead of at home.
But it went so well! I am finally feeling very comfortable with my corner gouge, and Juan's setup of sitting down with the mold resting on your knee and the block against the side of the bench for support and a cutting surface was very effective. With a proper light and this posture, it was so easy to make little, precise cuts.
At home I was hacking off big aggressive chunks on my cutting board, but Juan showed me how to just shave a little bit off from each side, flipping the mold over to reference the corner lines drawn on on each side of the block. I didn't falter as I cut the corners and they each turned out great. It may be the one thing I've done so far that I actually felt proud of as gouging finally felt comfortable and natural to me.
After cutting with the gouge I used my new $2.50 Harbor Freight file to smooth out then outsides of the corners and the new feather edge (or bee sting). Then Juan showed me his tiny scrapers that we used to just clean up the corners.
Before doing any of this cutting though, we used a square to draw a line on each corner leaving 2mm or rib wood from end of the corner to work with as far as feathering the edges goes. I did 3mm on the top corners because the tip of the top corner on my template didn't come to a clean point—it may have been chipped.