Products for bench top machinists | LittleMachineShop.com

Washer, 5/16" Hardened Black

Washer, 5/16" Hardened Black - Main image
$0.98 $1.49 In stock

This 5/16" hardened flat washer has a black finish and is offered under the McMaster-Carr brand. It is a fastening component intended for use with 5/16" hardware in bench top machining and assembly work.

  • Size: 5/16"
  • Type: flat washer
  • Construction: hardened
  • Finish: black
  • Brand: McMaster-Carr
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Customer Reviews (4.8 / 5 · 5 reviews)

Alexander T. ★★★★★

Noticed these don’t spin or wobble when torqued down on the bench fixture, and the hardened steel held up fine against the vise jaws without any gouging. They’re exactly the right thickness for 5/16” hardware, so no shimming needed.

Joseph ★★★★★

The black finish held up perfectly during a full day of bench work, no chips or peeling even after tightening and loosening the same bolts repeatedly. I grabbed a handful for a 5/16" fixture I was building and the fit was snug without any wobble, exactly what hardened washers should do.

Richard D. ★★★★★

These washers have a really consistent finish—no burs or uneven edges that snag during assembly. They sit perfectly flat against the bench top and work great for securing 5/16" hardware.