Boring bar clamp fixture - video

[Toolmaker51]

I'd argue flat head fasteners overall aren't first choice in tooling. The head diameter occupies proportionally a lot of space, undersides are not concentric to thread body, and reduced hex opening is small compared to same thread body, (limits torquing potential of that thread size). They also will not relocate a part dependably, some think, as substitute dowels. Their only saving grace is purely cosmetic, retaining thin covers and panels. Even then, many times cause issues in hole preparation, when countersink diameter to reach flush exceeds sheet thickness; worse yet too close to perimeter of part. What could be less cosmetic than that?