Mutual Screw & Supply

5/16-18 X 2-1/2" Hex Machine Bolts | 18/8 Stainless Steel | Partially Threaded (1000 / Pkg.)

5/16-18 X 2-1/2" Hex Machine Bolts | 18/8 Stainless Steel | Partially Threaded - Main image
$169.5 $226 In stock

5/16-18 X 2-1/2" Hex Machine Bolts in 18/8 Stainless Steel. A hex head machine bolt with a partially threaded shank per ASME B18.2.1, providing an unthreaded grip length for bolted connections through clearance holes.

  • Partially threaded shank for a smooth bearing surface in the shear plane of bolted joints
  • Hex head for wrench-driven, high-torque installation
  • Stainless steel for superior corrosion resistance

Specifications

  • Type: Hex Machine Bolts
  • Head Style: Hex
  • Material: 18/8 Stainless Steel
  • Finish: Plain
  • Thread Size: 5/16-18
  • Length: 2-1/2"
  • Thread: Partially Threaded
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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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Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

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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 (4.2 / 5 · 5 reviews)

Zoe I. ★★★★★

I needed bolts with precise grip length for a stainless marine railing repair, and the ASME B18.2.1 spec on these made fitting them perfectly straightforward. The 18/8 stainless finish looks clean and resists corrosion exactly as I hoped.

Violet ★★★★★

The partially threaded shank gave me just the grip I needed for a secure fit on my trailer hitch — no more guessing if the threads are taking all the load. These 18/8 stainless bolts feel solid and resist corrosion much better than the zinc ones I used before.

Chloe ★★★★★

I’ve used a lot of stainless hardware over the years, and this batch is consistent in both thread fit and finish. The 18/8 material feels solid and corrosion-resistant, and the unthreaded grip section sits flush in my fixture without any wobble. Packed tight with no bent threads, which is rare for a