The basics of our diaphragm centering technique consists of the use of stacks of laser-cut discs that have been cut to fit the profile to be centered and clamped.
The example shown here, the centering and clamping of a bar used to fabricate door-lock cylinders, uses discs that have been laser-cut to fit the profile of the bar on one side only. However the discs are stacked vice-versa to clamp on each side of the bar and a clamping mechanism (here a chuck) presses the discs against the bar. As a result one obtains a strong clamping and very precise thanks to the fact that the identical discs press from both sides cancelling possible fabrication errors of the discs.
Reasons to switch to the diaphragm centering:
Another example is this holder clamping hexagonal bits: