I had most of the part already machined out the night before, so all I needed to do was poke a few holes for the locating pins and cut it off the stand. For the holes, I used the 1/8" endmill I used to do the rest of the part with and did a pecking drill operation. I really shouldn't have done it with an endmill as it made the hole quite a bit wider than I wanted, and there is a bit too much wiggle room for my liking. If I thought about it, it makes sense, since endmills have side cutting capabilities, any kind of vibration would cut into the walls of the cylinder, whereas a drill bit would only cut down.
After milling out the holes, I then moved over to parting the piece off the base of the stock. This was much easier than I thought it was going to be, I created a sketch on the face of the side I wanted to mill from and made a rectangle in which I could restrict the path of the endmill. I then used an adaptive clearing to remove the material from underneath. Unfortunately, about halfway through the cutting operation, I forgot the stock wasn't perfectly square in the clamp, which caused the endmill to dive into 1/6" of aluminum thinking it was air; this flipped the stock partway out of the clamp. I did get it on camera, and you can almost hear me jump when it happens.
Thankfully I was able just to loosen the clamp a bit and get it back in place, and after that, it was pretty uneventful. I came in from the four different faces and cut each about 0.8" down then for the last operation left about 0.05," which I would cut off manually. I did this rather than having the endmill cut it all the way off in case the part fell and scraped up the finish on the piece.
I noticed that the holes for the set screw and pins didn't go all the way through the bottom of the part, so I took it over to the drill press and finished the job. I then used the small files I picked up last week to deburr the edges and clean off the bottom, where I parted it off the base.
I then took a piece of bar stock I had that this project was based around and drilled two 0.25" holes on the drill press to match the holes on the new clamp. Since the clamp screws I'd be using are smaller than the 0.25" holes, I had no problem aligning them appropriately to fit. After tightening the clamp screws, it was not going anywhere, super stable!
Since I also now have the new bed/disk that came in today, I removed the old clamp and installed it. It fit perfectly, and I only need to machine a few features on it before its ready for the part I just finished! I just rested the new clamp on the table to see how it would look in its final state.