Cylinder head screw 6-32" UNC-3/8 Allen key galvanized

Cylinder head screw 6-32" UNC-3/8 Allen key galvanized

Technical Product Specification
Designation: Socket Head Cap Screw (Hexagon Socket)
Thread: 6-32 UNC – 3/8" Length, Zinc Plated

1. Thread & Standards

Thread Size: No. 6 (nominal major diameter)

Thread Type: UNC (Unified Coarse) – American coarse thread series

Thread Pitch: 32 threads per inch (TPI)

Minor diameter (approx., for reference): 0.112″ (2.85 mm)

Standard: ASME B 18.3-03 (Socket Cap Head Screws)

2. Dimensions (metric conversions)

Nominal thread major diameter: 0.138″ = 3.51 mm (No. 6 UNC)

Nominal length (under head, L_UH): 3/8″ = 9.53 mm (tolerances per ASME B 18.3)

Overall length (approx.): ~0.453″ (11.5 mm) – head height dependent

Head diameter (approx.): 0.250″ (6.35 mm) per ASME B 18.3

Head height (approx.): 0.130″ (3.30 mm)

Hexagon socket size (key width): 7/64″ = 2.78 mm (standard for No. 6 size)

3. Material & Hardness

Material: Steel, suitable for heat treatment / quenching and tempering

Hardness: HRC 39 – 44 (Rockwell C scale)
→ This corresponds approximately to property class 10.9 – 12.9 (depending on heat treatment)

Surface finish: Zinc plated (electrolytically deposited; clear/blue or yellow passivated, depending on variant)

4. Environmental Compliance

RoHS compliant (2011/65/EU): Yes – free of Pb, Hg, Cd, Cr(VI), PBB, PBDE

REACH (SVHC): Available upon request (standard zinc plating typically complies)

5. Additional manufacturing & inspection data

Inspection standard: ASME B 18.3 – Section for socket head cap screws

Thread class: 2A (external thread, standard fit)

Recommended tightening torque (guideline, for 10.9 class): approx. 4 – 5 Nm (dependent on friction coefficient – to be verified case-by-case)

Corrosion resistance: Zinc plating (coating thickness approx. 5–8 µm) – suitable for interior use or mild outdoor exposure (neutral salt spray test: approx. 48–72 h without post-treatment)