What type of marking tool should you use when marking fastener locations on any part?

When marking fastener locations on any part, using a non-graphite pencil is the best choice due to its precision and the quality of the markings it produces. Non-graphite pencils, typically made from materials like colored wax or other non-metallic substances, ensure that the marks are clear and can be easily seen without the risk of contaminating the surface or leaving a residue that could affect the integrity of the material.

These markings are often important for ensuring the correct placement of fasteners, as they keep the assembly process organized and prevent mistakes. Additionally, the non-graphite nature of the pencil helps in avoiding potential electrical conductivity issues or metallic contamination that could arise from using graphite-based materials. This quality makes it particularly suitable for high-precision environments, such as aerospace assembly, where cleanliness and accuracy are paramount.

In contrast, marking tools like marker pens, chalk, or highlighters may not offer the same level of precision, permanence, or material compatibility that a non-graphite pencil provides. They can smear, wear off, or leave residues that might compromise the quality of the assembly. Therefore, the use of a non-graphite pencil is the most reliable choice for marking fastener locations effectively.