For line-shaft hardware, collars, and similar mechanical locations, 1/4-20 x 3 1/2 gives buyers the square-head set screw style named on many older drawings.

Typical applications include older machine tools that were designed around wrench-driven set screws. Use the size to match the thread and length, then call out Half Dog, Full Dog, Cone, Oval, or Flat as the required point. Flat points bear against a machined flat without intentional penetration into the mating surface.

Cold Headers can review less-common square-head sizes, long lengths, and point combinations when the standard catalog matrix does not cover the need. The family runs UNC coarse thread throughout, the traditional square-head series. Cup Point Slotted Headless Set Screws are the related headless option when flush-fitting screwdriver access is preferred.

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: 1/4-20 (UNC)
• Thread Fit: 2A (per ASME B18.6.2)
• Length: 3 1/2 in.
• Width Across Flats (F): 0.250 / 0.241 in. (max/min)
• Across Corners (G): 0.354 / 0.331 in. (max/min)
• Head Height (H): 0.196 / 0.178 in. (max/min)
• Dimensional Standard: ASME B18.6.2

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