I'm looking for advice on the most efficient method to cut a slot that's 3/16" wide and 1.25" deep along the length of a 2X4. This is for a fencing project where I need to cut multiple boards, so I'm hoping to avoid complicated setups for each board. I've been considering using a dado blade on a table saw, but I'm not sure if it will go deep enough. I've also thought about using a straight bit router, but I wonder if that would require multiple passes. Using a circular saw with an edge guide seems tricky since they don't make blades that are 3/16" thick. Is this feasible?
4 Answers
You'll need to adjust whatever method you pick. I’d recommend using a router table and making multiple depth passes. Start with a shallow cut on all boards, then deepen the cut and repeat until you reach the depth you need. Just don't go too deep with each pass—1/4" is a good max depth for safety. It'll be efficient doing it this way!
If you're going the table saw route, just set your fence for the right distance from the edge of the board, make your cuts from both sides, and you'll get a clean slot. Full kerf blades are about 1/8", so you won't even need to clear out the center because the cuts will overlap just fine by 1/16". It's super straightforward!
Oh that's clever! I like that method.
If you're cranking out a lot of these, consider investing in a 3/16" flat top grooving blade. They run between 100-150 bucks, but they'll save you time in the long run!
For me, a table saw is the best option. A router would take way too long with all those passes for that depth. You can dial in your width with some test cuts and probably get it done in two passes without adjusting the fence—just flip the board and go again!
That makes sense about the router. I like it, same idea as TimberTinkerer89.

I think this would work. It just might be too much setup compared to the idea from TimberTinkerer89. Thanks for the suggestion!