7/8-9 x 5 1/2 is a low carbon steel, case hardened square head set screw for wrench-driven holding where an external square head is acceptable.

Typical applications include mill and conveyor drives where square-head hardware remains accessible during service. Because point style changes the mating contact, buyers should specify Half Dog, Full Dog, Cone, Oval, or Flat with the size. Flat points bear against a machined flat without intentional penetration into the mating surface.

Cold Headers supports square-head set screw sourcing with a catalog organized around exact size, standard, and point selection. The family runs UNC coarse thread throughout, the traditional square-head series. For cup point square heads, use the separate Cup Point Square Head Set Screws category rather than this five-point family.

Technical Highlights

• Head: Square, wrench-driven
• Material: Low Carbon Steel, Case Hardened
• Point Styles: Half Dog, Full Dog, Cone, Oval, Flat (specify at order)
• Thread Size: 7/8-9 (UNC)
• Thread Fit: 2A (per ASME B18.6.2)
• Length: 5 1/2 in.
• Width Across Flats (F): 0.875 / 0.852 in. (max/min)
• Across Corners (G): 1.237 / 1.170 in. (max/min)
• Head Height (H): 0.678 / 0.635 in. (max/min)
• Dimensional Standard: ASME B18.6.2

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