Mutual Screw & Supply

5/16-18 X 1-1/4" Hex Head Cap Screws | USA Made | Grade L9 Alloy Steel Yellow Zinc | Fully Threaded (100 / Pkg.)

5/16-18 X 1-1/4" Hex Head Cap Screws | USA Made | Grade L9 Alloy Steel Yellow - Main image
$57.73 $86.16 In stock

5/16-18 x 1-1/4" hex head cap screws for machinery, equipment assembly and general industrial fastening.

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

Specifications

  • Thread Size: 5/16-18
  • Length: 1-1/4"
  • Threads Per Inch: 18
  • Material: Alloy Steel
  • Grade: Grade L9
  • Finish: Yellow Zinc CR+3
  • Thread Style: Fully Threaded
  • Pack Quantity: 100
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Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

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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 (5.0 / 5 · 5 reviews)

Avery W. ★★★★★

The yellow zinc finish on these is genuinely nice—no flaking even after I torqued them down with an impact driver. Grade L9 alloy steel feels plenty tough for my equipment frame, and the fully threaded length made alignment a breeze. These are my new go-to for any 5/16-18 job.

Henry ★★★★★

These bolts worked perfectly for securing a new mill table, and the yellow zinc coating makes them easy to spot against gray steel. The L9 grade gives me real confidence they’ll hold up under heavy cutting loads.

Brian F. ★★★★★

Installed these on a heavy-duty jig I’m building, and the L9 grade is noticeably tougher than standard hardware. The yellow zinc finish slides into the socket smoothly, and every single bolt threaded cleanly—no duds in the hundred-count pack.