Because the folded over piece is exactly half the width of your router base, your router will be perfectly centered. (full size)
in Centering Router Dado Jig
This photo was taken 6 years ago in Des Moines, Iowa with a Google Pixel 3.
It's also on Flickr.
Derek Brooks posted 5 years ago
comments
The beauty of this is:
1. That you only measure and operate on center lines. You never have to find the edges and make sure you're on the right side of the line, etc.
2. That this jig will work with whatever size bit you throw on the router.
And that's it.
Derek Brooks posted