[ParisDakar]

I haven't checked the plates for flatness. But I'll do that when we get a minute and let you know.

As for the calculations, my best guess was that the horizontal milling forces acting on the hinge would be similar to pushing a car over a curb. If the wheels have x amount of weight on them, how hard do you have to push horizontally to get the wheels to climb the curb. The height of the curb would equate to the depth of the groove.

Of course the hinge won't roll like a wheel. And the milling forces don't produce a straight push on the hinge, it's more of a horizontal torque. So my model isn't an exact approximation.