Today I fabricated the other eccentric using the threaded rod. It went much faster, about an hour start to finish.
I then went through the book noting the dimensions, calculating the 1.5x dimensions and writing them on the pages, and comparing these to the brass material I have on hand. It seems I either have pieces that are too small, much too big, or else I need to make a part to fit another part that gets made first.
However I do have a number of pieces of 1/4" thick brass sheet that was originally 3" wide. Since I now had the eccentrics made it seemed logical to make the straps next. I found two pieces that were reasonably close to the top and bottom sections, squared the sides on the mill, measured each with the height gauge to calculate how much needed to be milled off, and then milled both to the calculated size.
The only point of interest to a reader might be this "technique" for clamping a part in the mill that is thinner than your parallels:

These hardened precise cylinders are also useful in ensuring proper clamping when the surface against the moveable jaw is not flat.
Once both pieces were sized and precisely squared, I drilled the holes for the screws. I am using 6-32 screws. Once the top piece was drilled and tapped, and the mounting surfaces deburred, I screwed the two tightly together and camped in the vise in order to bore the hole.
The diameter of the groove in the eccentrics is ~.830, so I wasn't going to be able to find a "lucky fit" drill bit as Bogs did. So after edge finding to locate the center of the bore, I center drilled and drilled through with the 1/2" drill bit. Then I remembered that I have a .75" end mill, and used this to enlarge the hole further. Then I had to resort to the boring head to reach the final dimension. I recently acquired a set of bore gauges, and these were immensely useful in measuring the bore with the piece still in the vise. I used Bogs' tolerance of .05mm, which is ~.002.
Next I used a 1/2" endmill to reduce the thickness of the strap (still screwed together) to fit the width of the groove in the eccentric, taking equal amounts on both sides. This also cleaned up the surface on the sides.
When assembled onto the eccentric it turned, albeit stiffly. Some lapping and run-in should take care of the fit (I hope).
Then I reclamped the top portion in the vise to drill the holes for the coupling. It seems that 3/16" rod would be a bit too big, so I drilled it 5/32. Then drilling the oil hole completed the day's shop activity. Here's the result of about 5 hour's work:

