I'll second that...
I agree with my friend Stephen and others on this one. It's the riveted stiffener plate that gives this joint its strength. The small gap is of no consequence, and the rounded flange is okay, too. But like Stephen, I got another scotchbrite wheel, the finer one, and I've used both of them throughout the build.
I had a problem early on with my scotchbrite wheel, and I would urge you to avoid it if you can. If you're not careful, your work will cut a groove in the wheel. The one on the left is the one I'm really talking about. It's the worst one. And as if that wasn't bad enough, I allowed my wheel to develop a slope to it:
The reason this got so bad is because I thought the groove was cool at first, thinking it would allow me to deburr both sides and the edge of the work at the same time. Don't do this! It ended up cutting the groove deeper and deeper and before I knew it, it was grabbing the work and almost yanking it out of my hand. I have a more thorough discussion of it right here in my log, along with more pictures and my attempt at fixing it:
March 29, 2008 Log
The way I avoid any further grooves is to always hold the work at a slight sideways angle on the wheel and keep moving it from side to side.
My bench grinder is mounted on this stand, which you can make or get one from Sears/Craftsman. It's at just the right height, easy to move around, and both sides have total freedom of clearance.
Good luck on your project! Keep us posted, will you?