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Complete guide: M3–M24 dimension table, grade 08.8 explained, DIN7984 vs DIN912 vs DIN6912 comparison, selection guide & ordering format.
DIN7984 is a metric low-head hex socket cap screw with no pilot recess, head height ~60% of DIN912, rated grade 08.8 or A2-070 — the standard choice when DIN912 won’t fit the clearance but a plain hex key is still required.
The head has a plain hex socket — no center guide hole. This means:
✓ Standard hex keys work directly (no DIN6911 guided key required)
✓ Full flush seating — head bearing face contacts workpiece directly
✓ Grade is written 08.8 (zero prefix = reduced head loadability; never write 8.8 for DIN7984)
Shank tensile strength equals standard 8.8 (~800 MPa), but head bending resistance is rated lower due to reduced head geometry. Stainless grades: A2-070 and A4-070 (zero prefix always required).
DIN7984 vs DIN912 vs DIN6912 — Key Differences
Three standards, three distinct use cases. Choosing the wrong one means incompatible tooling, a seating gap, or unnecessary strength penalty.
| Feature | DIN912 (Standard Head) | DIN7984 (Low Head, No Pilot) | DIN6912 (Low Head + Pilot Recess) |
|---|---|---|---|
| Head Height (k) | Full height | ~60% of DIN912 | ~60% of DIN912 |
| Pilot Recess (Guide Hole) | None | None | Yes — requires DIN6911 key |
| Hex Key Type Required | Standard hex key | Standard hex key | DIN6911 guided hex key |
| Can Screw Seat Flush to Surface | Yes | Yes | No (pilot recess creates unthreaded gap) |
| Hex Socket Size (s) | Larger (matches nominal diameter) | Slightly larger than DIN6912 | Smaller (reduced by pilot hole) |
| Strength Grade Notation | 8.8 / 10.9 / A2-70 | 08.8 / A2-070 / A4-070 | 08.8 / A2-070 / A4-070 |
| Typical Use Case | High-strength general assembly | Low clearance, flush-fit, standard tools | Narrow space, anti-slip tool alignment |
DIN7984 Full Dimensions Table
Complete M3–M24 dimension data per DIN7984 standard. All values in millimeters. Non-preferred sizes (M14, M18, M22) shown in parentheses.
| Thread d | Pitch P (mm) | Head Dia. dk (mm) | Head Height k (mm) | Hex Socket s (mm) | Key Depth t (mm) | Thread b (L≤125) | Thread b (125<L≤200) | Thread b (L>200) |
|---|---|---|---|---|---|---|---|---|
| M3 | 0.50 | 5.5 | 2.0 | 2 | 1.5 | 12 | — | — |
| M4 | 0.70 | 7 | 2.8 | 2.5 | 1.8 | 14 | — | — |
| M5 | 0.80 | 8.5 | 3.5 | 3 | 2.1 | 16 | — | — |
| M6 | 1.00 | 10 | 4.0 | 4 | 2.5 | 18 | — | — |
| M8 | 1.25 | 13 | 5.0 | 5 | 3.0 | 22 | — | — |
| M10 | 1.50 | 16 | 6.0 | 7 | 3.5 | 26 | 32 | — |
| M12 | 1.75 | 18 | 7.0 | 8 | 4.0 | 30 | 36 | — |
| (M14) | 2.00 | 21 | 8.0 | 10 | 4.5 | 34 | 40 | — |
| M16 | 2.00 | 24 | 9.0 | 12 | 5.0 | 38 | 44 | 57 |
| (M18) | 2.50 | 27 | 10.0 | 12 | 5.5 | 42 | 48 | 61 |
| M20 | 2.50 | 30 | 11.0 | 14 | 6.0 | 46 | 52 | 65 |
| (M22) | 2.50 | 33 | 12.0 | 14 | — | 50 | 56 | 69 |
| M24 | 3.00 | 36 | 13.0 | 17 | — | 54 | 60 | 73 |
Sizes in parentheses (M14, M18, M22) are non-preferred. b = minimum thread length. dk = head outer diameter, k = head height, s = hex socket across flats, t = key engagement depth.
Materials & Strength Grades
Grade notation uses a zero prefix for all DIN7984 specifications. Never omit the leading zero: 08.8, A2-070, A4-070.
| Material | Grade Notation | Typical Application |
|---|---|---|
| Carbon Steel | 08.8 | General mechanical assembly, indoor |
| Stainless Steel 304 | A2-070 | Light corrosion, food equipment, medical |
| Stainless Steel 316 | A4-070 | Marine, chemical, outdoor exposure |
| High-Strength SS 316 | A4-080 | High torque + corrosion combined |
| Carbon Steel + Finish | 08.8 BLK | Tooling, fixtures, aesthetic finish |
Surface finishes: Plain | Black oxide | Zinc white | Dacromet | PTFE
Key Applications
- Panel & cover plate fastening — M5 (3.5 mm head) fits where DIN912 M5 (5 mm head) cannot.
- Aluminum T-slot extrusion assembly — M5 and M6 in 80/20, Bosch Rexroth, Misumi systems.
- Thin-wall sheet metal joining — Low profile without requiring a countersink.
- Electronics & enclosure assembly — M3 and M4 in A2-070 stainless; non-magnetic, corrosion-neutral.
- Precision jigs, fixtures & CMM tooling — Head height tolerance aids stack-up calculations.
- Automation & robotics frames — M8/M10 in cobot brackets and linear actuator frames.
How to Select: DIN7984 vs DIN912 vs DIN6912
Step 1: Is installation clearance limited?
→ No → Use DIN912 (higher strength, larger socket, simpler procurement)
→ Yes → Continue to Step 2
Step 2: Must the screw sit fully flush with the workpiece surface?
→ Yes → DIN7984 (no pilot recess, full flush seating, standard hex key)
→ No → Continue to Step 3
Step 3: Is anti-slip tool guidance required in deep blind-hole access?
→ Yes → DIN6912 + DIN6911 guided key (cam-out prevention)
→ No → DIN7984 (standard hex key, flush seating, simpler tooling)
Ordering Format: Screw DIN7984 – M8 × 20 – 08.8
- DIN7984 — always include the DIN prefix
- M8 — nominal thread diameter
- × 20 — nominal length in mm (underhead to tip, includes head height)
- 08.8 — zero-prefix grade (never write 8.8 for DIN7984)
Stainless example: Screw DIN7984 – M6 × 16 – A2-070
Frequently Asked Questions — DIN7984
Need DIN7984 in Custom Sizes or Bulk Quantities?
We supply DIN7984 low head socket cap screws in carbon steel 08.8, stainless A2-070 and A4-070, and special finishes including Dacromet and black oxide. MOQ as low as 100 pcs.