Which standard defines dimensions for bolts, nuts, and washers?

The organization that is responsible for addressing dimensional guidelines and tolerances for fasteners is the American Society of Mechanical Engineers (ASME). This organization was founded in 1880 and now has over 130,000 members in 151 countries. In addition to being a standards organization, ASME is also involved in research and development, training and professional development, conferences and publications, and government relations.

Here are the ASME dimensional standards for common construction fasteners:

ASME B18.2.1 Hex bolts, heavy hex bolts, square head bolts This specification covers head height, width across the flats, width across the corners, and several other dimensions.
ASME B18.5 Carriage bolts, round head bolts, countersunk bolts This specification covers head height, head diameter, size of the square neck of carriage bolts, countersunk head angle, and several other dimensions.
ASME B18.2.2 Hex nuts, heavy hex nuts, square nuts, hex jam nuts, heavy hex jam nuts, hex coupling nuts, lock nuts Nut height, width across the corners, and width across the flats of the nut are the three primary dimensions specified under this standard.
ASME B18.2.6 Structural bolts This standard outlines head dimensions and other measurements for heavy hex structural bolts.
ASME B18.21.1 Standard flat washers, lock washers This washer standard includes dimensions for thickness, inside diameter, and outside diameter.

Portland Bolt manufactures fasteners with head dimensions that comply with these standards. We will also automatically provide submittal drawings which states our fasteners will meet the ASME standards. If you have any questions about ASME standards or anything else, feel free to contact our team and we will be more than happy to assist.

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    I am a teacher and I’m trying to develop a lesson on creative design. I am from the construction industry, and I want to illustrate all the different stages involved in product development in order to help my students understand that EVERY piece of the finished products, down to the nuts and bolts, that they may interface with or be affected by is the result of intelligent design. My target audience is 10-14 years old.
    To that end, I was wondering if you might be able to supply me with some images of two nuts and bolts with different specs. (pitch, hardness, etc.) Just a couple images would suffice. A technical design drawing with the specifications detailed would be great. Also, if you have one, a picture of one of your draftsmen or engineers at his drafting table or computer. Just to illustrate how the product begins with a man with an idea for creating it and then a machinist at his equipment station. Anything you could provide would be extremely helpful.
    Do you think you would be able to provide me with this type of information? It would be greatly appreciated. If so, please contact me:
    David Gray

    @David- I will email you some literature shortly. Thank you for reaching out, we are always happy to help.

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