It was decided to use a 4” air chuck mounted on a 4th axis (rotary table). The CNC operator machined the soft jaws to fit into the back of the workpiece, ID clamping in the 5mm hole (see photo). When the chuck is in an open position, it clamps the workpiece allowing tools access from both surfaces.
The milling operation is done by one clamping, savings the extra handling (set-up) of the workpiece loading and unloading for the second operation. No need to orient the workpiece for the second operation. Needless to say that one operation is always better and more accurate than two.
milling a tiny workpiece
This is a small workpiece 7.5mm long by 7mm diameter. In the production plan, it was directed to machine it in two operations, meaning two clamps, set-up twice. The first one is for milling the front section and the second is for the back section.