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Use the 1-8 x 5/16 18-8 stainless hex head cap screw when the assembly calls for side wrench access and a general-purpose bolt pattern. In this size range it is treated as a hex head cap screw, with the hex head driven by external tooling rather than an internal socket.

Common application reviews include HVAC equipment, conveyor structures, and retrofit repairs. Use it through a clearance hole with a nut or into a prepared tapped hole when the drawing calls for a stainless hex-head fastener.

18-8 stainless steel is an 18% chromium and 8% nickel austenitic stainless material used for ordinary atmosphere, moisture exposure, washdown, and clean appearance. Cold Headers serves maintenance and production needs where exact-size stainless hardware matters more than generic substitution.

Technical Highlights

  • Material: 18-8 Stainless Steel
  • Thread Size: 1-8
  • Length: 5/16 in.
  • Head Style: Hex
  • Drive: External Hex (wrench or socket driven)
  • Width Across Flats: 0.489-0.500 in.
  • Wrench Size: 1/2 in.
  • Head Height: 0.195-0.211 in.
  • Dimensional Standard: ASME B18.2.1
  • Material Standard: ASTM F593

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

Unit of Measure

Specifications

Brands

 N/A Cold Headers, Inc.

Diameter

 N/A 1-8

Length

 N/A 5/16 in

Maximum Width Across the Flats

 N/A 0.500 in

Minimum Width Across the Flats

 N/A 0.489 in

Maximum Width Across Corners

 N/A 0.577 in

Minimum Width Across Corners

 N/A 0.557 in

Maximum Head Height

 N/A 0.211 in

Minimum Head Height

 N/A 0.195 in

Material

 N/A 18-8 Stainless Steel

Package Type

 N/A Each

Search

 N/A SSHHCMS.1-8.5/16

Note

Note

 N/A Less Than Package Quantity Specified Plus 25%.