Mutual Screw & Supply

5/16-18 X 3" Hex Head Cap Screws | USA Made | Grade L9 Alloy Steel Yellow Zinc | Partially Threaded (100 / Pkg.)

5/16-18 X 3" Hex Head Cap Screws | USA Made | Grade L9 Alloy Steel Yellow Zinc - Main image
$125.32 $187.04 In stock

5/16-18 x 3" hex head cap screws for machinery, equipment assembly and general industrial fastening.

  • Grade L9 Alloy Steel Yellow Zinc construction
  • Partially Threaded
  • Hex head for wrench or socket drive
  • Made in the USA
  • Sold in packs of 100

Specifications

  • Thread Size: 5/16-18
  • Length: 3"
  • Threads Per Inch: 18
  • Material: Alloy Steel
  • Grade: Grade L9
  • Finish: Yellow Zinc CR+3
  • Thread Style: Partially Threaded
  • Pack Quantity: 100
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Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

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Delivery costs

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Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

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Returning an item

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United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

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Customer Reviews (4.6 / 5 · 5 reviews)

Kevin ★★★★★

The threading is clean and the yellow zinc finish feels durable, so they drove into my equipment mounts without any binding. Partially threaded gave me just the right grip for the heavy assembly, and all 100 came uniform straight out of the box.

Leo ★★★★★

Grade L9 alloy steel is no joke — these bolts took a serious amount of torque on my shop press frame without a hint of stripping. The yellow zinc finish is consistent across all 100, and the partial threading makes alignment way easier than fully threaded ones I’ve used before.

Lucy ★★★★★

The partial threading on these 5/16-18 x 3” bolts is spot on for my jig setup, and the yellow zinc finish has held up well against shop grime. Grade L9 alloy steel feels plenty tough for the bracket I’m securing, and the hex heads seated cleanly with a socket.