ISO 8733 Parallel Pins with Internal Thread
ISO 8733 parallel pins with internal thread, d1 m6 6 to 50 — the extractable precision dowel for large diameters, with the collected c1/c2/d2/P/d3/t1/t2/t3 attribute rows and the full standard-length matrix (l 16 – 200).
Last updated: 2026-11
Specifications
ISO 8733 solves the extraction problem of the big plain dowel: once a d40 parallel pin is pressed into a housing, you cannot pull it — so this standard threads an internal socket (d2: M4 at d1 6 up to M24 at d1 50) into the pin's bore, and a puller screw extracts it for teardowns and re-machining. The precision is the dowel family's: d1 ground to m6 tolerance, chamfers c1/c2 per diameter, and the internal thread spec carried fully — pitch P, bore d3, thread depth t1, usable depth t2, and the t3 countersink that clears the extraction screw head. The collected ladder runs d1 6 to 50 with the internal-thread rows (note the deliberate thread repeats in the source: M6 shared at d1 10/12, M20 at d1 30/40 — the bore is sized by the nearest practical tap, not scaled with the pin). The standard-length matrix runs l 16 to 200 with min./max. tolerance pairs (±0,5 to l 50, ±0,75 above) and the source's "x" availability marks per diameter — read together they define what a supplier can offer without machining. Ordering discipline: quote d1 × length and the extraction-screw access on the assembly side (the t3 countersink sits at the pin face). Compare ISO 8734 (plain parallel dowel, this catalog's x39 page) below d1 50 where extraction never matters. Material, hardness and finish are not tabulated — per RFQ (dowel-grade hardened steel is the trade default, confirm at quotation).
| Standard | ISO 8733 — parallel pins with internal thread (extractable precision dowels) |
|---|---|
| Size range | d1 m6: 6 – 50, ten diameters in the collected rows |
| Internal thread | d2: M4 (d1 6) → M24 (d1 50); P, d3, t1/t2/t3 rows carried per diameter |
| Chamfer / radius | c1: 0,8 → 6,3; c2: 1,2 → 8 per diameter |
| Length matrix | l 16 – 200, min./max. ±0,5 (to 50) / ±0,75 (above), source "x" availability marks |
| Material / hardness | Not tabulated by the collected specification — per RFQ |
| Attribute | 6 | 8 | 10 | 12 | 16 | 20 | 25 | 30 | 40 | 50 |
|---|---|---|---|---|---|---|---|---|---|---|
| c1 | 0,8 | 1 | 1,2 | 1,6 | 2 | 2,5 | 3 | 4 | 5 | 6,3 |
| c2 | 1,2 | 1,6 | 2 | 2,5 | 3 | 3,5 | 4 | 5 | 6,3 | 8 |
| d2 | M4 | M5 | M6 | M6 | M8 | M10 | M16 | M20 | M20 | M24 |
| P | 0,7 | 0,8 | 1 | 1 | 1,25 | 1,5 | 2 | 2,5 | 2,5 | 3 |
| d3 | 4,3 | 5,3 | 6,4 | 6,4 | 8,4 | 10,5 | 17 | 21 | 21 | 25 |
| t1 | 6 | 8 | 10 | 12 | 16 | 18 | 24 | 30 | 30 | 36 |
| t2 | 10 | 12 | 16 | 20 | 25 | 28 | 35 | 40 | 40 | 50 |
| t3 | 1 | 1,2 | 1,2 | 1,2 | 1,5 | 1,5 | 2 | 2 | 2,5 | 2,5 |
| Nominal | min. | max. | 6 | 8 | 10 | 12 | 16 | 20 | 25 | 30 | 40 | 50 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 16 | 15,5 | 16,5 | x | |||||||||
| 18 | 17,5 | 18,5 | x | x | ||||||||
| 20 | 19,5 | 20,5 | x | x | ||||||||
| 22 | 21,5 | 22,5 | x | x | x | |||||||
| 24 | 23,5 | 24,5 | x | x | x | |||||||
| 26 | 25,5 | 26,5 | x | x | x | x | ||||||
| 28 | 27,5 | 28,5 | x | x | x | x | ||||||
| 30 | 29,5 | 30,5 | x | x | x | x | ||||||
| 32 | 31,5 | 32,5 | x | x | x | x | x | |||||
| 35 | 34,5 | 35,5 | x | x | x | x | x | |||||
| 40 | 39,5 | 40,5 | x | x | x | x | x | x | ||||
| 45 | 44,5 | 45,5 | x | x | x | x | x | x | ||||
| 50 | 49,5 | 50,5 | x | x | x | x | x | x | x | |||
| 55 | 54,25 | 55,75 | x | x | x | x | x | x | x | |||
| 60 | 59,25 | 60,75 | x | x | x | x | x | x | x | x | ||
| 65 | 64,25 | 65,75 | x | x | x | x | x | x | x | |||
| 70 | 69,25 | 70,75 | x | x | x | x | x | x | x | |||
| 75 | 74,25 | 75,75 | x | x | x | x | x | x | x | |||
| 80 | 79,25 | 80,75 | x | x | x | x | x | x | x | x | ||
| 85 | 84,25 | 85,75 | x | x | x | x | x | x | x | |||
| 90 | 89,25 | 90,75 | x | x | x | x | x | x | x | |||
| 95 | 94,25 | 95,75 | x | x | x | x | x | x | x | x | ||
| 100 | 99,25 | 100,75 | x | x | x | x | x | x | x | x | ||
| 120 | 119,25 | 120,75 | x | x | x | x | x | x | x | |||
| 140 | 139,25 | 140,75 | x | x | x | x | x | x | ||||
| 160 | 159,25 | 160,75 | x | x | x | x | x | x | ||||
| 180 | 179,25 | 180,75 | x | x | x | x | x | |||||
| 200 | 199,25 | 200,75 | x | x | x | x | x |
Materials
- Material and hardness specified per RFQ — precision dowels are commonly hardened and ground alloy steel (the m6 tolerance is ground, not rolled); state the housing material and whether the extraction screw will be stainless against the pin at quotation
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 (ISO 8733 Parallel Pins with Internal Thread) 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 do I need an internally threaded parallel pin instead of a plain dowel (ISO 8734)?
Size and service life. A plain parallel dowel is cheaper and simpler — until it has to come out. Above roughly d1 16–20 the interference fit of a ground dowel resists every puller jaw you can bring; the internally threaded ISO 8733 pin carries an extraction socket sized to the pin (the collected d2 row: M6 at d1 10–12, M8 at 16, M10 at 20 … M24 at 50), so a screw-based puller removes it axially without wrecking the housing bore. That pays for itself in die sets, heavy machine builds and anything with a planned rebuild. Below that size band, or in assemblies that never come apart, the plain x39 page is the economical order. Three evidence-backed cautions: first, the length matrix defines availability — the "x" marks thin out at the extremes (d1 6 stops at l 60; l 200 starts at d1 20), so quote the ladder, not a wish. Second, the thread repeats in the source (M6 at both d1 10 and 12; M20 at 30 and 40) are the standard's own — not capture defects. Third, the extraction side needs the t3 countersink clearance in the mating part's drawing. Material, hardness and finish stay per RFQ.
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