Legs first… I know this seems backwards (especially given the various blogs and books on the subject) but I’m going to give it a shot.
My neighbor gave me a 12’ 6×6 pressure treated beam. I read somewhere that you should not use this stuff in the shop, but I’ve been around the stuff my whole life and it hasn’t affected me. Nevertheless, that’s what I’m using for the legs. I cut the legs to 35” on the chopsaw and planed them square (they were far from square) to about 5.25” x 5.25”.
Then I used the tablesaw to cut the tenons. I will post some pictures of my setup later, but it was pretty simple. My benchtop is going to be built out of 2×4s (1.5” wide construction grade), so I used a 2×4 as my guide and drew some horizontal lines across the top of the leg where the bench will be. Then I setup a vertical tenon cutting jig on the tablesaw and cut those lines (cutting to the waste side of the line). My ridgid tablesaw can cut up to 3.5” deep, which is perfect my 2×4 top. After making my primary vertical cuts (3 of them), I laid the leg flat and cut the rear shoulder off. Then I stood it back up and made several vertical cuts to remove the waste (much like a dado blade would). I cleaned up the middle with a wide chisel.
I thought the front angled cuts would be difficult, but they were actually pretty easy. I don’t trust my handsaw skills yet, so I did the following to get a good kerf: put the tablesaw blade at a 45, align the fence to take off the corner (take time getting this aligned) and make a 1” deep cut. If your leg is square, you can turn it over and make your other cut. Square leg, 45 degree angles, couldn’t be simpler. Finish the vertical cut with a handsaw. Then I cut the shoulder off.
When I was done, I tested the fit with a 2×4… fit pretty snug.