Three supports under the base, two against the long edge, and another stop touching the short flange; the flange contact is where some samples feel high.

Is that flange controlled from the same drawing datums as the base?

I wouldn't rule the clamp out completely. A bad direction of force can make a sensible nest misbehave. But if yours already rocks before clamping, I'd start with those supports and actual bracket sizes.

Do the same samples rock every time, Yasmin? That might help you separate a part difference from something left on a support.

Two samples rock repeatedly before clamping; the others sit without that feel, and I have checked the bench supports for loose debris.

Could be burrs on the bracket too. I wouldn't spot small ones from CAD.

Photograph each sample seated and lifted off. The contact area matters more than another overhead shot of a tidy fixture. Your designer can then connect a measurement to the place that's touching.

Zara, did your bent parts recover after unclamping, or had the fixture permanently changed them? We have had both, and the second version is an expensive way to discover a bad locating idea.

They stayed bent. We scrapped that trial batch. Different parts from Yasmin's, obviously, but it cured me of treating clamp force as free improvement.

The designer has measured the two rocking samples and found the short flange position differs within its drawing allowance; he is reviewing that contact against the locating datums.

So the drawing permits the variation. That's useful to know before someone sends acceptable parts back as defective. Has he proposed a relieved contact or a different locating face?

No revised design yet; thanks for making me ask about datums, Jonas, because I had only compared the nominal dimensions.

I'd like to hear what he chooses. Relief might solve the conflict, but you still need that last movement constrained somewhere appropriate. The stronger clamp can remain in the sales catalogue for now.