What information is required to properly denote fasteners in assembly BOMs?

• A. Fastener thread, fastener head type, overall fastener length
• B. Material, finish, and coating type
• C. Quantity, supplier, and batch number
• D. Vendor, price, and lead time

Answer: (A)

When specifying fasteners in an assembly BOM, you need the attributes that uniquely identify the fastener’s size and fit. The thread (which includes the nominal diameter and pitch) tells you what holes or nuts it will engage and how it mates with other parts. The head type indicates the drive style and how the fastener sits in the assembly, affecting clearance and appearance. The overall length ensures the fastener will thread in properly and reach the required depth without protruding or being too short. Together, these three characteristics pinpoint the exact fastener to use.

Material, finish, and coating type matter for performance and durability, but they can vary among parts with the same size and head style, so they don’t uniquely define the fastener at the BOM level. Quantity, supplier, and batch number relate to procurement and traceability rather than identifying which fastener is used. Vendor, price, and lead time are procurement details, not part identities.