DIN 6912 Low Head Socket Cap Screw | A2 Stainless Steel (SUS304) | Pilot Recess

FULLERKREG DIN 6912 Low Head Socket Cap Screws — A2 Stainless Steel (SUS304) | Pilot Recess

FULLERKREG DIN 6912 low head socket cap screws are precision-engineered metric fasteners combining a reduced-height hex socket head with a pilot recess (centre hole) in the socket — the defining feature that distinguishes DIN 6912 from the standard DIN 912 socket cap screw. The pilot recess enables use of a ball-end hex key at angles up to 25°, making these screws ideal for confined spaces and recessed installations where straight-on access is impossible.

Manufactured from A2 stainless steel (SUS304), FULLERKREG DIN 6912 screws offer excellent corrosion resistance, good mechanical strength, and a clean natural finish — suitable for food processing, marine, medical, architectural, and general industrial applications.


Key Features

  • Standard: DIN 6912 — Hexagon socket head cap screws with low head and pilot recess
  • Material: A2 Stainless Steel (SUS304 / 1.4301) — austenitic, non-magnetic in annealed state
  • Property Class: A2-70 (per ISO 3506-1)
  • Head Style: Low profile (reduced height) hex socket cap head — approximately 60% of standard DIN 912 head height
  • Drive: Internal hex (Allen / hex socket) with pilot recess (centre hole)
  • Pilot Recess Advantage: Allows ball-end hex key engagement at up to 25° angle — critical for blind or angled access
  • Thread: Metric coarse thread (ISO 68-1), right-hand
  • Surface: Natural (as-machined) stainless — no coating required
  • Size Range: M3 to M20

DIN 6912 vs. DIN 7984 vs. DIN 912: Key Differences

Feature DIN 6912 (This Product) DIN 7984 DIN 912 (Standard Socket Cap)
Head Height Low (approx. 60% of DIN 912) Low (approx. 60% of DIN 912) Standard full height
Pilot Recess (Centre Hole) ✅ Yes — centre hole in socket ❌ No ❌ No
Ball-End Hex Key Access ✅ Up to 25° off-axis ⚠️ Limited — ball-end slips without pilot ⚠️ Limited — ball-end slips without pilot
Hex Key Size (e.g. M6) 4 mm 3 mm (smaller than DIN 6912) 5 mm (full size)
Head Diameter dk (e.g. M6) 10.0 mm 10.0 mm 10.0 mm
Head Height k (e.g. M6) 3.3 mm 3.0 mm 6.0 mm
Socket Depth (e.g. M6) Deeper — accommodates pilot recess Shallower — no pilot recess Full depth standard socket
Torque Capacity Medium — larger hex key than DIN 7984 Lower — smaller hex key size Full torque capacity
Clearance Required Minimal — ideal for thin flanges Minimal — ideal for thin flanges Standard clearance needed
Governing Standard DIN 6912 / ISO 14580 DIN 7984 DIN 912 / ISO 4762
Best For Low clearance + angled access required Low clearance, straight-on access only General-purpose, high-torque applications

Material & Mechanical Properties

Manufactured from A2 stainless steel (SUS304 / EN 1.4301) — the most widely used austenitic stainless steel grade, offering an excellent balance of corrosion resistance, formability, and weldability.

Property Value Standard Reference
Material Grade A2 (SUS304 / 1.4301) ISO 3506 / EN 10088
Property Class A2-70 ISO 3506-1
Tensile Strength (min.) 700 MPa ISO 3506-1
0.2% Proof Stress (min.) 450 MPa ISO 3506-1
Elongation (min.) 20% ISO 3506-1
Hardness (max.) 220 HV ISO 3506-1
Magnetic Non-magnetic (annealed state)
Corrosion Resistance Excellent — resists atmospheric, freshwater, mild chemical
Operating Temperature −50°C to +300°C (continuous)

Dimensional Specifications (DIN 6912)

All dimensions per DIN 6912:2021. Thread per ISO 68-1 metric coarse.

Size Thread Pitch (mm) Head Dia. dk (mm) Head Height k (mm) Hex Key Size s (mm) Pilot Recess Dia. (mm) Common Lengths (mm)
M3 0.5 5.5 1.65 2.0 1.0 5, 6, 8, 10, 12, 16, 20
M4 0.7 7.0 2.2 2.5 1.5 6, 8, 10, 12, 16, 20, 25
M5 0.8 8.5 2.75 3.0 2.0 8, 10, 12, 16, 20, 25, 30
M6 1.0 10.0 3.3 4.0 2.0 10, 12, 16, 20, 25, 30, 35, 40
M8 1.25 13.0 4.4 5.0 2.5 12, 16, 20, 25, 30, 35, 40, 50
M10 1.5 16.0 5.5 6.0 3.0 16, 20, 25, 30, 35, 40, 50, 60
M12 1.75 18.0 6.6 8.0 4.0 20, 25, 30, 35, 40, 50, 60, 70
M14 2.0 21.0 7.7 10.0 4.0 25, 30, 35, 40, 50, 60, 70, 80
M16 2.0 24.0 8.8 10.0 4.0 25, 30, 35, 40, 50, 60, 70, 80, 100
M20 2.5 30.0 11.0 12.0 5.0 30, 35, 40, 50, 60, 70, 80, 100

All dimensions are nominal per DIN 6912:2021. Consult FULLERKREG product listings for exact available size/length combinations. Tolerances per ISO 4759-1.


The Pilot Recess: Why It Matters

The pilot recess (also called centre hole or pilot hole) is a small cylindrical bore at the centre of the hex socket. It serves two critical functions:

  • Ball-end hex key engagement: The pilot recess guides and stabilises the ball end of a ball-point hex key, allowing reliable torque transmission at angles up to 25° off-axis. Without the pilot recess, ball-end keys tend to slip out of the socket under load.
  • Alignment aid: The recess acts as a visual and tactile centre reference during assembly, reducing the risk of cam-out and socket damage.

This feature makes DIN 6912 the preferred choice over DIN 7984 for recessed bolt patterns, flanged joints, and any assembly where the fastener is not directly accessible from above.


Corrosion Resistance of A2 Stainless Steel

A2 (SUS304) stainless steel forms a passive chromium oxide layer that self-repairs when exposed to oxygen, providing durable corrosion protection in a wide range of environments:

  • Atmospheric exposure — urban, industrial, and rural environments
  • Freshwater immersion — potable water systems, food processing
  • Mild chemical exposure — dilute acids, alkalis, and organic compounds
  • Food contact — compliant with food-grade requirements (non-toxic, non-leaching)
  • ⚠️ Chloride environments — A2 is susceptible to pitting and crevice corrosion in high-chloride (marine/coastal) environments; use A4 (SUS316) for such applications
  • Strong reducing acids (e.g., hydrochloric, sulphuric) — not recommended

Typical Applications

  • Thin-flange and low-clearance assemblies where standard socket cap head height is too tall
  • Precision machinery, instrumentation, and optical equipment requiring flush or near-flush fastening
  • Food processing equipment, pharmaceutical machinery, and cleanroom assemblies
  • Marine deck hardware and boat fittings (sheltered/freshwater environments)
  • Architectural metalwork, facade systems, and interior design fixtures
  • Medical devices and laboratory equipment requiring corrosion-free, non-magnetic fasteners
  • Electronics enclosures and PCB mounting where non-magnetic properties are required
  • Automotive and motorsport components in corrosion-prone locations
  • Any assembly requiring angled hex key access due to obstructions or recessed bolt patterns

Installation & Torque Guidelines

Recommended installation torque values for A2-70 DIN 6912 screws (dry, unlubricated, μ = 0.12):

Size Recommended Torque (N·m) Hex Key Size (mm) Notes
M3 0.5 – 0.7 2.0 Use T-handle or short-arm key; avoid over-torque
M4 1.2 – 1.5 2.5
M5 2.5 – 3.0 3.0
M6 4.5 – 5.5 4.0
M8 11 – 13 5.0
M10 22 – 26 6.0
M12 38 – 45 8.0
M14 60 – 72 10.0
M16 95 – 110 10.0
M20 185 – 215 12.0

Torque values are indicative for dry conditions with standard thread fit. Lubrication reduces required torque by approximately 20–25%. For critical joints, use a calibrated torque wrench and refer to joint-specific engineering calculations. A2 stainless is susceptible to galling — apply anti-seize compound (e.g., molybdenum disulphide or copper-based) for M10 and above, or where repeated assembly/disassembly is required.


Anti-Galling Note for Stainless Steel Fasteners

Stainless steel fasteners — including A2 — are prone to galling (cold welding / thread seizure) during installation, particularly at larger diameters and higher torques. To prevent galling:

  • Apply a thin coat of anti-seize compound (molybdenum disulphide, copper-based, or PTFE-based) to the thread and under the head before installation
  • Drive at low speed — avoid high-speed power tools without torque control
  • Ensure threads are clean and free of debris before assembly
  • Use A2 nuts with A2 screws — mixing grades increases galling risk
  • If galling occurs during removal, apply penetrating oil and use a slow, steady torque — do not force

Compliance & Standards

  • DIN 6912:2021 — Hexagon socket head cap screws with low head and pilot recess
  • ISO 3506-1 — Mechanical properties of corrosion-resistant stainless steel fasteners — bolts, screws and studs
  • ISO 68-1 — Metric screw threads: General plan
  • ISO 4759-1 — Tolerances for fasteners
  • EN 10088 — Stainless steels: List of stainless steels (1.4301 / SUS304)
  • RoHS compliant — no restricted substances in A2 stainless steel

Packaging & Supply

  • Available in bulk bags, plastic boxes, and custom packaging for OEM and MRO supply
  • Standard packaging quantities: 10 pcs, 25 pcs, 50 pcs, 100 pcs, 500 pcs (size-dependent)
  • Wholesale and B2B pricing available — contact FULLERKREG for volume quotations
  • Full material certifications (mill certs, ISO 3506 compliance) available on request
  • Custom lengths and non-standard sizes available on request (MOQ applies)
  • RoHS and REACH compliant documentation available

Why Choose FULLERKREG DIN 6912 A2 Stainless?

  • Manufactured to DIN 6912:2021 dimensional standards — not nominal equivalents
  • A2-70 mechanical properties verified per ISO 3506-1 with full traceability
  • Pilot recess geometry precisely formed for reliable ball-end hex key engagement at up to 25°
  • Full size range M3–M20 with broad length availability for versatile application coverage
  • Consistent natural stainless finish — no coating variation or adhesion concerns
  • Competitive lead times for standard sizes; custom configurations on request
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