Grade 2: no markings (weakest) | Grade 5: three radial lines spaced 120 degrees apart (medium strength) | Grade 8: six radial lines spaced 60 degrees apart (strongest) |
- 8.8: indicated as such on the head and is equivalent to a Grade 5 (weaker)
- 10.9: indicated as such on the head and is equivalent to a Grade 8 (stronger)
- Grade 2: no markings
- Grade 5: three radial lines spaced 120 degrees apart. It could also be a dot and a line, the line being 120 degrees counterclockwise from the dot
- Grade 8: six radial lines spaced 60 degrees apart. It could also be a dot and a line, the line being 60 degrees counterclockwise from the dot
There are two main patterns that a flat washer can follow: USS or SAE. They are the Society of Automotive Engineers (SAE) and United States Standard (USS). SAE flat washers can be identified as the washers have a smaller outer diameter (OD) and inner diameter (ID) than the same nominal size (bolt size) USS washers – with the exception of our close tolerance USS washers which have a tighten ID for increased strength in high load applications.
Torque:
By giving the proper torque to your fastening system, you help assure that the fastening system is tightened to the right specification that is the correct clamping force to hold the assembly together.
Clamping force is attained when the fastener is tightened and begins to stretch. Much like a rubber band, the more you stretch it, the more it attempts to pull itself back together and the more clamping force is developed – up to a point. While steel stretches, it will break if you tighten it too much. At some point continued tightening will cause the fastener to break when its ultimate tensile strength is exceeded. An overtightened fastening system can result in the system failure. Other factors that can result in failure include a mismatched fastening system, poor installation, and reusing a previously overtightened, and stretched, bolt.
If you want to learn more about fastenening systems and best practices, hbspt.cta._relativeUrls=true;hbspt.cta.load(2451464, ‘b7529126-4fef-41a4-a61c-424dd49644a0’, {“useNewLoader”:”true”,”region”:”na1″});
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