In a part number, how can you identify a bolt with a drilled head?

In part numbering systems, specific designations are used to indicate particular characteristics of the components. A bolt with a drilled head is commonly denoted by the letter E in the part number. This designation refers specifically to the feature of having a hole drilled into the head, which may be designed to accommodate safety wires or diminish weight.

The letter D typically relates to a different characteristic or specification in the part numbering scheme, while the number R may signify yet another feature unrelated to the drilling of the head. The letter A is also indicative of a separate classification within bolt designations and does not represent a drilled head configuration. Therefore, recognizing the unique attribute represented by the letter E is key to identifying a bolt with a drilled head in the context of engineering and manufacturing standards.