I am picking up automatic door bottoms for my place and I need to mortise the bottom of the door about 1" wide by 1 3/4" deep to install them. Looking around online, I haven't been able to find anything other than a jig that festool makes for it's routers. Even if I owned a festool router, $365 for that jig is far too much for me to spend.

Browsing online, I found this installation video where they use a similar type jig but unfortunately don't call out the name of the product. Anyone have any ideas?

Here is the installation video I'm referring to.

https://www.youtube.com/watch?v=xt50ay1fQBQ