Question is directed towards the engineers and machinists here. I think this is primarily a system designed to keep the clamping faces parallel, and perhaps there is some kind of bushing or shoulder bolt.
more context
I know a typical screw and nut in a pair of scissors will not align the blades well enough. I want to understand what kinds of hand finishing processes might be used to remedy the alignment problem. Like is this pictured example using a wave or crush washer to compensate for the alignment variation induced by the thread helix and pitch clearance, or something else likely going on? Does this kind of fastener have a name? Is there a more general variant with wrench flats on both sides or does this design typically require a more involved tooling to create?
In other words I want to have an abstract understanding of the entry point, nuances of application, and investment required to incorporate the design into other DIY type projects. For (a rough) instance, I have run into similar issues with the alignment of optics such as with image sensors.
Hard to say exactly what they did without taking it apart, but it kinda looks like the washers might be springs. Concave when loose and flat under tension. That would help to keep the blades close together even after heavy use and wear.
I would assume that the inside face of the bolt has a square or rectangular profile that seats into the hole to prevent it from turning. The nut looks like it was custom made for this use.
The nut and the bolt could be made in small quantities on a metal lathe. For large quantities they would likely be made on a screw machine. The washers are probably an off-the-shelf part but could also be made on a screw machine.