I've owned one of the best routers ever made. It's an ELU ... bought out by Dewalt and rebadged as the DW624/625. It's a beast with advanced features still leading the industry today.
I also have several other routers. The most recent, and I expect will be most used, is the DCW600. It's handheld and powered by a 20v battery.
This article isn't about the router, though. It's about a jig that makes it efficient and simple to use. First, some history.
I was a fan of Bob Rosendahl on the show The Router Workshop. One aspect of his show was his accuracy in dados and rabbets. He rarely used measuring tapes ... he used other techniques to get the actual width and depth. The show went on the air in 1982 and lasted 12 years. I actually have two of the products they manufactured and sold. One is a brass width/depth system, the other is one of their desktop router tables and insert. I have discarded the table, kept the insert. Bob's technique of accurate "measurement" was a game changer ... not only in the use of the router, but in woodworking in general.
In the photo at the left, Bob is on the left. Bob was very proud to have his son, Rick, co-host the show with him in later years.
This latest game changer came from searches on YouTube for a better saw guide. There's quite a few ... the vast majority are useless fluff. But one video hit the mark.
The "talking head" under the name Casual DIY calls this the "The ONLY Jig You Need? Cuts Perfectly Straight with 3 Different Tools!" I need to point out a few flaws in this design. One major flaw is the router edge is on the left side of the guide arm. The only way this can work properly is if you are pulling the router towards you. That's counter-intuitive. There are many instructional videos on the proper direction for a rabbet cut (as well as dados) ... to make this article a tad shorter, the guide has to position the router on the ride side – not the left side. I suspect Casual DIY was inspired by another video (made 7 months earlier) for a 2-in-1 solution and modified his design for one-upmanship.
The other video by @abiraffawoodwork is the game changer.
This video correctly has the router positioned at the right of the guide arm – that's the right direction for rabbets. The direction also works for dados. For both rabbets and dados you still need to keep some pressure on the router to stay straight to the guide. That's to protect you from the possibility of going cross-grain. And if you know you are cross-grain, go slow to minimize tear-out.
A bit too technical there. The concept of this is outstanding.
I ended up purchasing a 24" T-Square while it was on a clearance sale at Princess Auto (Canada's version of - or similar to - Harbor Freight). I had always expected to use this as a saw guide, but I will modify the T-Square to use this new game changer concept. Mine will use the 2-in-1 design.