For the end caps I decided to use some walnut I bought a while ago. I went with a standard C-channel end cap. I really wanted to do a sliding dovetail, but it seemed a little too difficult at this point in my woodworking.
First I cut a straight edge with my circular saw across the end. I flipped it over and offset my cut 1/16” and finished the cut. Then I used a pattern bit and cleaned up the 1/16” excess. I read somewhere this method was much easier that attempting to match up the circular saw cuts, and I think that is true. This is prior to cutting the shoulders for the end cap.
To cut the shoulders (not really sure what to call them), I considered using a router. It seemed like that would take forever and I always seem to wobble the router and take out a chunk and screw up the project. So I used my circular saw. I set the depth @ 15/16” and setup a cutting guide. I made several straight cuts, then I slightly turned the saw and pushed it through. The saw guide prevented me from unnecessarily cutting into the benchtop (beyond the edge of the end caps). I learned this method watching my father in law cut dadoes in 6×6’s when constructing decks.
I cleaned it up with a chisel.
Then I took my end caps to the tbsw and setup my dado stack and cut the female portion of the joint. I used several test pieces of scrap lumber to get the fit right.
After I got the fit right, I counterbored three holes in each end cap. Then I fastened the end cap to the top with three 2” lag bolts.
The finished benchtop.