What is the function of 100-degree open countersinks in assembly work?

The function of 100-degree open countersinks in assembly work primarily relates to ensuring a proper fit for fasteners. When a countersink is created at a 100-degree angle, it allows for the rivet or screw head to sit flush with or slightly below the surface of the material. This is especially important in aerospace applications where aerodynamics and structural integrity are essential.

By providing relief for fillet edges, the countersink facilitates a smooth transition between the fastener and the material, allowing for better load distribution and reducing the potential for stress concentration around the joint. This is particularly critical in areas where materials may be joined that have differing thicknesses or where the flow of air or fluids is significant.

Moreover, a correctly executed countersink helps to avoid protrusions that could interfere with surrounding components, thereby enhancing the overall assembly's performance and safety. The taper from the countersink also helps in aligning the fastener properly during installation, contributing to an efficient assembly process.