I am currently trying to design a mounting bracket for a picatinny rail. One of the problems I've encountered is that if the screws are placed at a 90 degree angle, the section below it is too thin; about 1mm. This is due to the concave shape at the bottom. The issue with this is that if it was pulled upwards, it will easily break out of the fixture. I initially thought that I could move the drilled section up or reduce the thickness of the screw, but due to the design this is not really possible.
I've thought about it and decided that if one were to angle the screws a little bit - around 30 degrees - you'd be able to alleviate the issue somewhat. The only issue now is that I have to somehow ensure the screw heads are not just sticking out. I've googled and I've found "angled washers" and "hillside washers", but they're too big or I have to order a thousand from a manufacturer. Is there some more effective way that I can do this?
Are you assuming that the vertical surfaces have to be vertical? Do they really? Can you create a surface perpendicular to the screw threads?