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Internet # 310484631

Model # 9090912

5/16 in.-18 x 1 in. Zinc Plated Case Hardened Steel Serrated Flange Bolts (25-Pack)

  • Flange helps eliminate need for a washer
  • Designed for general applications
  • Steel construction offers long-lasting use and solid performance
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Product Details

About This Product

Flange bolts feature a built in washer under the bolt head that helps to distribute the clamping load over a larger area. This "one-piece" design eliminates the need of a separate washer under the bolt head and is preferable for some applications as it can be more efficient and easier to use. A washer is still needed on the nut side unless using a flange nut. The serrations under the flange bite into the surface and help to resist loosening due to vibration.


  • Size: 5/16 inch-18 X 1 inch
  • Hex bolt with a serrated circular flange under the head
  • Flange eliminates need for separate washer
  • Serrations bite into surface and can help to prevent loosening
  • Designed for use with a nut (not included) or a threaded hole of the same diameter and thread size
  • Thread type: coarse, thread class: UNC-2A, point style: blunt
  • Specification(s) met: ASME B18.2.1, ASME B18.6.3, and ASME B1.1
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Product Information

Internet # 310484631

Model # 9090912

Additional Resources

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From the Manufacturer


Dimensions: H 0.65 in, W 0.45 in, D 1.25 in


Assembled Depth (in.)

1.25 in

Assembled Height (in.)

0.65 in

Assembled Width (in.)

0.45 in

Fastener Length (in.)

1 in

Head diameter (in.)



5/16 in


ACQ Rated Fastener


Fastener Length

1 in

Fastener Plating


Fastener Type

Hex Bolt




Not Graded



Measurement System


Package Quantity


Product Weight (lb.)

0.04 lb



Thread pitch


Thread Style

Coarse Thread

Warranty / Certifications

Manufacturer Warranty

Goods are warranted against manufacturing defects for 1 year. In no case is Prime-Line responsible for user related damage or damage incurred during installation. Warranty is void if products are subjected to abnormal conditions, misapplication or abuse.

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5 out of 5

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Everything I expected but I with the online order, my...
Everything I expected but I with the online order, my delivery time was 3 to 5 days but then that turned into over 2 weeks.
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