What is the term for a shallow recess used to create a bearing surface for a fastener?

The term for a shallow recess that is created to provide a bearing surface for a fastener is a "spotface." This feature is typically machined onto a surface to ensure that fasteners, such as bolts or screws, can sit flat and make proper contact with the material. Spotfacing is especially important in applications where a smooth and snug fit is necessary for effective load transfer and to prevent loosening from vibration or movement.

The depth and diameter of the spotface are designed to accommodate specific fasteners, facilitating the use of larger or stronger fasteners and ensuring that the fastener is not located too close to an edge of the material, which could cause structural failure.

Understanding the purpose of a spotface is critical in engineering design, as it enhances the integrity and functionality of the assembly.