I'd do it as a 4 jaw chuck project. Face one surface, flip it & make the other 3 surfaces perpendicular/parallel to the first surface, turn the 25 mm spigot then flip it & make the threaded hole - I'd single point it instead of buying a special tap. After cutting the thread, hacksaw a slit in the middle & use a couple of headless set screws to spread things apart to take up backlash.
"Numb" for "nub" looks like auto-correct rearing its head.
Roy?
