Mutual Screw & Supply

HOLO-KROME 72020 #4-40 X 3/8" Socket Cap Screws | Hex Socket Drive | Alloy Steel Thermal Black Oxide (100 / Pkg.)

HOLO-KROME 72020 #4-40 X 3/8" Socket Cap Screws | Hex Socket Drive | Alloy - Main image
$19.09 $31.81 In stock

These #4-40 x 3/8" socket cap screws are manufactured from Alloy Steel Thermal Black Oxide, featuring a socket drive. They are well suited to machinery, tooling, jigs, and precision assemblies.

  • Material and finish: Alloy Steel Thermal Black Oxide
  • Drive: Socket Drive
  • Thread size: #4-40
  • Length: 3/8"
  • Applications: Machinery, tooling, jigs, and precision assemblies

Specifications

  • Product type: Socket Cap Screws
  • Material: Alloy Steel
  • Finish: Thermal Black Oxide
  • Drive type: Socket Drive
  • Thread size: #4-40
  • Length: 3/8"
  • Threads per inch: 40
  • Measurement type: Inch
  • Pack quantity: 100 per package
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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)

Emily Q. ★★★★★

The hex drive on these #4-40 screws fits perfectly into my tooling jigs, and the alloy steel feels incredibly sturdy for such a small fastener.

Emily D. ★★★★★

These are exactly what I needed for a small jig I was building; the #4-40 threads cut cleanly into the tapped holes. The hex socket drive made tightening them down in a tight spot much easier than a standard slotted screw would have been.

Michael ★★★★☆

The black oxide finish on these screws gives them a nice, uniform look that’s held up well in my tooling setup. I did have to chase a couple of them with a tap to clean the threads, but for a hundred pieces at this price, that’s a minor trade-off.