Mutual Screw & Supply

5/16-18 X 3-1/2" Machine Screws | Flat Head Phillips Drive | 18/8 Stainless Steel (100 / Pkg.)

5/16-18 X 3-1/2" Machine Screws | Flat Head Phillips Drive | 18/8 Stainless - Main image
$45.15 $61.85 In stock

18/8 (304) stainless steel machine screw offering strong corrosion resistance for indoor, outdoor, and washdown environments. Non-magnetic.

Specs

  • Dimensions: 5/16-18 3-1/2"
  • Drive type: Phillips
  • Head style: Flat Head
  • Material: 18/8 Stainless Steel
  • Thread: 5/16-18 UNC (coarse)

Features

  • Machine-thread screws for use with nuts or tapped holes
  • Flat head profile
  • Phillips drive
  • 18/8 Stainless Steel construction
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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 (5.0 / 5 · 5 reviews)

Miles ★★★★★

Used these to mount a heavy bracket to a steel beam, and the 3-1/2 inch length gave me just enough thread engagement without being too long. Flat head sat flush with the surface perfectly. So far no rust even after a week of rain.

Evelyn ★★★★★

I needed some high-torque stainless fasteners for a boat railing repair, and these 18/8 screws felt substantial and seated perfectly in the pre-tapped holes. The flat heads sat flush without any burrs, which saved me a ton of sanding time—definitely what I needed.

Alexander ★★★★★

The Phillips head on these machine screws bit perfectly without any cam-out, which made installing them in a tight spot much less frustrating. They feel solid and the stainless steel finish looks clean against the wood.