DIN 7979D Pull Dowels (Parallel Pins with Internal Thread, Type D Hardened)
Hardened parallel pins with internal thread per DIN 7979D, type D — nominal diameters 6 to 80 mm at m6 tolerance in the collected table, each with its matching internal puller thread (M4 at Φ6 up to M42 at Φ80), thread hole d3, thread depths t1/t2, and the a1/a2/c1/c2 end dimensions.
Last updated: 2026-11
Specifications
A pull dowel is a parallel dowel pin built for removal: the same precision m6 press fit as ISO 8734, but with an internal thread tapped into the blind end so a extracting screw can pull the pin back out of its bore. That one feature solves the classic dowel problem — a plain dowel pressed into a housing has nothing to grip for extraction, so servicing means pressing or drifting it out and risking bore damage. The collected DIN 7979D table (type D = hardened) pairs every nominal diameter Φ6 to Φ80 with a matched puller thread: M4 at Φ6 stepping through M6 at Φ10–12, M8 at Φ14–16, M10 at Φ20, up to M42 at Φ80, with the tapped-hole depth t1, the minimum full-thread depth t2 and the thread-hole diameter d3 printed per size. The a1/a2 and c1/c2 end dimensions complete the geometry. For the tapered variant of the same idea, see the DIN 7978 internal-thread taper pin page.
| Standard | DIN 7979D — parallel pins with internal thread, type D = hardened, m6 tolerance |
|---|---|
| Size range | Nominal diameters Φ6, 8, 10, 12, 14, 16, 20, 25, 30, 40, 50, 60, 70, 80 mm |
| Pin diameter d (max/min by size) | m6 bands: 6.012/6.004 at Φ6 to 80.03/80.011 at Φ80 — see per-size table |
| Puller thread d2 (by size) | M4 (Φ6), M5 (Φ8), M6 (Φ10, Φ12), M8 (Φ14, Φ16), M10 (Φ20), M16 (Φ25), M20 (Φ30, Φ40), M24 (Φ50), M30 (Φ60, Φ70), M42 (Φ80) |
| Thread hole d3 (by size) | 4.3 mm at Φ6 to 43 mm at Φ80 — see per-size table |
| Thread depths t1 / t2 min (by size) | t1 6 mm at Φ6 to 63 mm at Φ80; t2 min 10 mm at Φ6 to 82 mm at Φ80 — see per-size table |
| End dimensions a1 / a2 (≈ by size) | a1 1.2 to 14 mm, a2 0.8 to 12 mm across the series — see per-size table |
| Chamfers c1 / c2 (≈ by size) | c1 0.6 to 8 mm, c2 2.1 to 16 mm across the series — see per-size table |
| Extraction | Screw into the internal thread and pull — no press or drift needed; t2 is the minimum thread engagement depth the extraction screw needs |
| Nominal diameter d | d max (mm) | d min (mm) | Thread d2 | d3 (mm) | t1 (mm) | t2 min (mm) | a1 approx. (mm) | a2 approx. (mm) | c1 approx. (mm) | c2 approx. (mm) |
|---|---|---|---|---|---|---|---|---|---|---|
| 6 | 6.012 | 6.004 | M4 | 4.3 | 6 | 10 | 1.2 | 0.8 | 0.6 | 2.1 |
| 8 | 8.015 | 8.006 | M5 | 5.3 | 8 | 12 | 1.6 | 1 | 0.8 | 2.6 |
| 10 | 10.015 | 10.006 | M6 | 6.4 | 10 | 16 | 2 | 1.2 | 1 | 3 |
| 12 | 12.018 | 12.007 | M6 | 6.4 | 10 | 16 | 2.5 | 1.6 | 1.2 | 3.8 |
| 14 | 14.018 | 14.007 | M8 | 8.4 | 12 | 20 | 2.5 | 1.8 | 1.4 | 4 |
| 16 | 16.018 | 16.007 | M8 | 8.4 | 12 | 20 | 3 | 2 | 1.6 | 4.7 |
| 20 | 20.021 | 20.008 | M10 | 10.5 | 16 | 25 | 3.5 | 2.5 | 2 | 6 |
| 25 | 25.021 | 25.008 | M16 | 17 | 24 | 34 | 4 | 3 | 2.5 | 6 |
| 30 | 30.021 | 30.008 | M20 | 21 | 30 | 42 | 5 | 4 | 3 | 7 |
| 40 | 40.025 | 40.009 | M20 | 21 | 30 | 42 | 6.3 | 5 | 4 | 8 |
| 50 | 50.025 | 50.009 | M24 | 25 | 36 | 50 | 8 | 6.3 | 5 | 10 |
| 60 | 60.03 | 60.011 | M30 | 31 | 40 | 56 | 10 | 8 | 6 | 12 |
| 70 | 70.03 | 70.011 | M36 | 37 | 54 | 71 | 12 | 10 | 7 | 14 |
| 80 | 80.03 | 80.011 | M42 | 43 | 63 | 82 | 14 | 12 | 8 | 16 |
Materials
- Material and finish specified per RFQ — the collected specification table covers geometry only
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 7979D Pull Dowels (Parallel Pins with Internal Thread, Type D Hardened)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantities and lead times for this family are confirmed at quotation — send your sizes, grades and quantities on the RFQ and the quote will carry a firm schedule. Sample availability is confirmed with the quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When is the extra cost of a pull dowel justified?
Wherever the doweled assembly is a scheduled-service item. In a mold, die or fixture that will be stripped and rebuilt, a plain dowel (ISO 8734) becomes a destructive-extraction problem every rebuild: press pulls bend plates, drifts mushroom the bore mouths. The DIN 7979D pin gives the same m6 located joint in service but lets a technician thread in a bolt and withdraw the pin cleanly. One-offs and joints that never come apart do not need it — the plain dowel is simpler and cheaper. The collected table shows the puller thread scales with pin size (M4 on a 6 mm pin, M42 on an 80 mm pin), so extraction force is not the limiting factor; plan the clearance for the extraction screw stroke when laying out the joint.
What should an RFQ for this pin type state?
State the pin type, the standard designation, the nominal size and length, material if the drawing names one, and quantity per size — plus destination country. Commercial terms are confirmed at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support