This is the second part of the articulating spacer
Here is the Fusion 360 drawing of the relevant part.
This second piece is the rear plate that measures 10x100x16mm
I did not take a full set of machining pictures for this one, as it is not a particularly complex part.
The first operation was to square it up and then drill and tap 4 M8 holes at on a central 88x45mm rectangle.
I also drilled a hole in the centre to be the starting point for the slot.
The slot is 44x16mm, this was milled using progressively larger end mills until I could use a 16mm mill for the final pass.
A simple piece of machining with no dramas in the making.