Bought this black walnut cookie off of Facebook marketplace for a good price. The only catch is it is warped, cracked, cupped, and twisted. It's about 4 in thick and that's plenty of material to make a coffee table, but I need some advice and guidance on making a router planing jig please.
YouTube is definitely your friend here. So many great woodworking channels. There's a woman who does this kind of project all the time, and unfortunately her channel name escapes me. If I can find it again, I'll add a comment for you.
I am interested in what you come up with for this. I have a router and a large table top I made, that due to my novice woodworking abilities, is not flat.
Tearout would be my biggest concern. Hand planing a board with fairly straight grain? No biggie. Hand planing something like hickory with crazier grain? That can be a pain. I imagine a cross section like this would be difficult to manage.
I have used a hand plane to flatten coffee tables in the past, but I don't think it would work well with the circular grain pattern and it would take me a week. Plus walnut is hard as heck.
A hand plane is for both thicknessing and straightening a board. A hand plane does not remove the same amount of material unless the board is already flat. The long flat heel of the plane serves as a reference surface. There is some skill required to not taper the workpiece and you can use winding sticks to check your progress as you flatten the workpiece.
A router sled/CNC router will be able to accomplish the same thing.