Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
A286 Dowel Pins
A286 dowel pins are precision-ground cylindrical pins used as alignment fixtures, anti-rotation locators, or shear-load transmitters in mechanical assemblies. Distinguished from A286 shoulder bolts by absence of head and threads — pure cylindrical geometry with surface finish Ra ≤ 0.4 µm. TorqBolt manufactures A286 dowel pins to ISO 8734 (parallel pins, ground), DIN 7 (parallel pins, ground), DIN 6325 (parallel pins, m6 tolerance), ASME B18.8.2 (US dowel pins), and NAS 1351-N0 (aerospace) standards. Diameter range 1.5-50 mm metric and 1/16-1 inch with h7 (most common), m6, or k6 tolerance per drawing. Heat-treated to ASTM A453 grade 660 Class A from AMS 5731 bar — 130 ksi tensile, 95 ksi yield. The non-magnetic austenitic matrix and h7 precision tolerance make A286 dowel pins the standard for aerospace, instrumentation and precision-machinery alignment. See parent A286 fasteners, related shoulder bolts, and the canonical chemical composition, heat treatment.
About A286 Dowel Pins
A286 dowel pins are press-fit into a precision-reamed hole and provide axis-of-rotation alignment, shear-load transmission, or anti-rotation locator function. The cylinder is ground after solution treatment to h7 (±0.012 mm at 6 mm), m6 (interference fit, ±0.008 mm), or k6 (medium fit) tolerance per drawing. Surface finish Ra ≤ 0.4 µm achieved by post-aging cylindrical grinding. Each dowel pin is turned from A286 bar (AMS 5731) to oversize, solution-treated 1650 °F and aged 1325 °F per AMS 5737, then finish-ground on cylindrical grinder. End geometry per drawing: chamfered (DIN 7), domed (NAS 1351-N0), or square-cut (custom). The non-magnetic austenitic matrix (permeability < 1.005) is critical for precision instrumentation and aerospace electromagnetic-sensitive alignment.
A286 Dowel Pin Types & Standards
TorqBolt produces five primary A286 dowel pin configurations:
- Parallel pin h7 ground (ISO 8734 / DIN 7) — Standard precision-ground dowel pin — ⌀ tolerance h7, surface Ra ≤ 0.4 µm. Most common general-purpose dowel. 1.5-50 mm sizes.
- Parallel pin m6 (DIN 6325) — Slightly larger pin for press-fit (interference) installation in standard reamed hole. m6 tolerance: nominal +0.005 / +0.013 mm. Used where positive press-fit retention is required.
- Parallel pin k6 (DIN 7 medium fit) — Medium fit between h7 sliding fit and m6 press fit. Used where pin must be removable but with positive engagement.
- Aerospace dowel pin (NAS 1351-N0) — Aerospace-grade dowel pin — magnetic permeability < 1.005, AS9102 first-article inspection per AS9100D. Used on aircraft engine and structural alignment.
- Tapered pin (ISO 2339 / DIN 1) — Tapered cylinder (1:50 taper) — for self-aligning press-fit applications. Less common; mostly replaced by parallel pins with reamed hole.
A286 Dowel Pin Sizes & Tolerance Reference
| Diameter | h7 tolerance | m6 tolerance | k6 tolerance | Length range | Surface finish |
|---|---|---|---|---|---|
| 3 mm | 0 / -0.010 | +0.004 / +0.012 | +0.001 / +0.009 | 5-50 mm | Ra ≤ 0.4 µm |
| 5 mm | 0 / -0.012 | +0.004 / +0.012 | +0.001 / +0.009 | 5-80 mm | Ra ≤ 0.4 µm |
| 6 mm | 0 / -0.012 | +0.004 / +0.012 | +0.001 / +0.009 | 6-100 mm | Ra ≤ 0.4 µm |
| 8 mm | 0 / -0.015 | +0.006 / +0.015 | +0.002 / +0.010 | 8-100 mm | Ra ≤ 0.4 µm |
| 10 mm | 0 / -0.015 | +0.006 / +0.015 | +0.002 / +0.010 | 10-150 mm | Ra ≤ 0.4 µm |
| 12 mm | 0 / -0.018 | +0.007 / +0.018 | +0.002 / +0.012 | 12-200 mm | Ra ≤ 0.4 µm |
| 16 mm | 0 / -0.018 | +0.007 / +0.018 | +0.002 / +0.012 | 16-200 mm | Ra ≤ 0.4 µm |
| 20 mm | 0 / -0.021 | +0.008 / +0.021 | +0.002 / +0.015 | 20-200 mm | Ra ≤ 0.4 µm |
| 25 mm | 0 / -0.021 | +0.008 / +0.021 | +0.002 / +0.015 | 25-200 mm | Ra ≤ 0.4 µm |
A286 Dowel Pins Manufacturing Process
Every a286 dowel pins TorqBolt ships traces back to a vacuum-induction-melted plus vacuum-arc-remelted (VIM-VAR) ingot meeting AMS 5731 / 5732 chemistry. The complete process route:
- Bar input + cut to length: AMS 5731 bar drawn to oversize ⌀ + grinding allowance (~0.1 mm). Cut to dowel-pin length + facing allowance.
- Solution treatment: Vacuum heat-treat 1650 °F (899 °C) per AMS 5737 / ASTM A453 Class A. 1 hour per inch, oil-quench.
- Precipitation aging: 1325 °F (718 °C) for 16 hours, air-cool. Hardness 277-302 HBW post-aging.
- Cylindrical grinding (post-aging): CNC cylindrical grinder finishes ⌀ to h7 / m6 / k6 per drawing. Surface roughness Ra ≤ 0.4 µm achieved with 80-grit then 220-grit grinding wheels.
- End facing / chamfer: Both ends faced and chamfered per drawing — DIN 7 chamfered, NAS 1351-N0 domed, or custom square-cut.
- Length cut to final: Final length cut on cut-off saw with abrasive wheel — ±0.05 mm precision.
- Passivation per ASTM A967: Pickle + HNO₃ rinse + passivate Type II to remove free iron from grinding.
- 100 % dimensional inspection: Every dowel pin: ⌀ snap-gauge, length micrometer, surface Ra spot-check (1 per 100).
- Marking + bulk pack: Pins too small for individual marking — lot-marked container with heat traceability label. Bulk pack 100 / 250 / 500 pcs.
A286 Dowel Pins Inspection & Certification
Each lot ships with a signed inspection certificate. AS9100D-compliant aerospace lots include AS9102 first-article reporting on every new drawing or revision. Industrial orders default to EN 10204 type 3.1. Variant-specific inspection scope:
- 100 % ⌀ snap-gauge per drawing tolerance — h7, m6, or k6.
- 100 % length micrometer check — ±0.05 mm tolerance.
- Surface roughness Ra ≤ 0.4 µm spot-checked by profilometer (1 per 100 pins).
- End geometry verified — chamfer angle, dome radius, or square-cut squareness.
- Hardness sample 1 per 200 dowels per ASTM E384.
- Magnetic permeability < 1.005 per ASTM A342 on every aerospace lot.
- AS9102 first-article inspection on NAS 1351-N0 lots per AS9100D.
- Salt-spray ASTM B117 96-hour for passivated lots.
A286 Dowel Pins Torque & Assembly Practice
Dowel pins do NOT carry torque — they carry shear and provide alignment. Installation: press-fit into reamed hole using arbor press or hydraulic press. Press-fit force per DIN 6325 m6: typically 200-500 N for M5 m6 in steel hole, 1500-3000 N for M16 m6. h7 sliding fit requires no press force — slip in by hand, retain via gravity or secondary fastener. Removal: tap out from opposite end with a soft-faced punch (brass, aluminum) — never use steel punch (mars the dowel surface). Re-use: h7 dowels re-usable indefinitely; m6 dowels acceptable for 3-5 cycles before fit becomes loose.
A286 Dowel Pin Applications by Industry
Dowel pins provide precision alignment and shear-load transmission — applications:
- Aerospace engine module alignment: NAS 1351-N0 dowel pins between accessory gearbox modules, fuel-pump mounting blocks — h7 sliding fit ensures correct module position. A286 jet engine fasteners.
- Aerospace structural splice: Dowel pins in shear-load joints between fuselage frame and wing-spar splice plates — pin transmits shear; bolts maintain clamp.
- Industrial die / mould tooling: Dowel pins align stamping-press die halves, injection-mould halves — h7 fit allows assembly/disassembly without thread engagement.
- Robotics & automation: Dowel pins between robot joint segments — ensure correct angular and positional relationship after disassembly. Non-magnetic prevents encoder interference.
- Precision optical instrumentation: A286 dowel pins on optical bench mounts, laser collimator blocks, mass-spectrometer ion-source alignment. Permeability < 1.005 critical.
- Cryogenic / vacuum equipment: Dowel pins on LNG valve actuator alignment, hydrogen storage manifold, UHV chamber internal hardware. Retains h7 tolerance at -196 °C and 540 °C.
Governing Standards & Material Specifications
Every A286 fastener is released against the applicable industry standard. EN 10204 type 3.1 mill certificates ship with every order. See the consolidated A286 AMS / ASTM specifications hub.
| Authority | Specification | Coverage |
|---|---|---|
| ASTM | A453 grade 660 Cl. A/B/C/D | High-temperature bolting material |
| ASTM | A638 grade 660 Type 1/2 | Forged bolting stock |
| AMS | 5731 | Bar / forging — solution-treated |
| AMS | 5732 | Bar / forging — solution-treated and aged |
| AMS | 5737 | Bar — sol-treated and aged (precision) |
| UNS | S66286 | Material designation |
| DIN | 1.4980 / X5NiCrTiMoVB25-15-2 | European designation |
| EN | 10204 3.1 / 3.2 | Mill / third-party-witness certification |
A286 Dowel Pins vs Alternative Materials
Engineers compare A286 against three alternatives: A286 vs Inconel 718, A286 vs 17-4 PH, and A286 vs Waspaloy. Across the 540-700 °C operating window, A286 delivers the lowest cost per MPa of retained preload. See A286 equivalent grades.
How to Specify A286 Dowel Pins
A complete a286 dowel pins callout should include all eight elements: material spec, heat-treatment condition, dimensional standard, size, thread tolerance class, surface finish, marking, inspection certificate. Example callout:
Dowel pin, ISO 8734, A286 / UNS S66286, ASTM A453 grade 660 Class A, ST+A, ⌀ 6.0 mm h7 × 30 mm length, surface Ra ≤ 0.4 µm, both ends chamfered, passivated, EN 10204 3.1.
A286 Dowel Pins — Frequently Asked Questions
What is a dowel pin?
A precision-ground cylindrical pin used as alignment fixture, anti-rotation locator, or shear-load transmitter. Distinguished from shoulder bolts by absence of head and threads — pure cylindrical geometry. Press-fit or slip-fit into reamed holes.
What's the difference between h7 and m6 dowel pin tolerance?
h7 (most common): nominal ⌀ -0 to -0.012 mm — sliding fit, hand-installable into reamed hole, removable. m6: nominal ⌀ +0.004 to +0.012 mm — interference fit, requires press force to install, semi-permanent. k6: medium fit between h7 and m6. Choose by required retention vs serviceability.
What surface finish on an A286 dowel pin?
Ra ≤ 0.4 µm (≤ 16 µin) per ISO 8734 / DIN 7. Achieved by post-aging cylindrical grinding with 80-grit then 220-grit wheels. Aerospace NAS 1351-N0 may specify Ra ≤ 0.2 µm for high-precision applications.
Are A286 dowel pins magnetic?
No. Magnetic permeability < 1.005 verified on every aerospace lot per ASTM A342. Critical for instrumentation, MRI, magnetometer, and electromagnetic-sensitive precision alignment applications.
How do I install a press-fit (m6) A286 dowel pin?
Use arbor press or small hydraulic press. Apply axial force along the pin axis; press into pre-reamed h7 hole at room temperature. Press force: 200-500 N for M5, 1500-3000 N for M16. Do NOT hammer — eccentric force damages the pin and the hole. Once seated, the m6 interference (~0.005-0.012 mm) holds the pin without secondary retention.
Can A286 dowel pins be re-used?
h7 sliding fit: indefinitely re-usable. m6 press fit: 3-5 cycles before interference becomes inadequate (each press cycle galls a small amount of surface material). Aerospace alignment: typically replace dowels with each major maintenance cycle for safety.
What's the maximum length of an A286 dowel pin?
Standard production: 200 mm in ⌀ 12-25 mm; 100 mm in ⌀ 5-10 mm; 50 mm in ⌀ 1.5-3 mm. Custom-drawing parts longer — up to 500 mm in ⌀ 16-50 mm with extended grinding.
What end geometry on an A286 dowel pin?
ISO 8734 / DIN 7 default: 1.0 mm × 30° chamfer on both ends. NAS 1351-N0 default: 0.5 mm radius dome on both ends. Custom: square-cut, single-chamfer, single-dome — per drawing.
Can A286 dowel pins replace shoulder bolts?
Functionally similar (both provide precision alignment), but dowel pins lack threaded retention. Use dowel pins for pure alignment + shear-load transmission; use shoulder bolts when alignment + threaded retention combined required. Dowel + separate bolt is the typical splice-joint design.
Why TorqBolt for A286 Dowel Pins
Three reasons aerospace and gas-turbine OEMs place a286 dowel pins orders with us:
- Vertically integrated supply — VIM-VAR melt, in-house cold heading + thread rolling + vacuum heat-treatment.
- Aerospace AQMS — AS9100D-certified factory in Mumbai with published quality manual.
- Lead time discipline — 4-6 weeks standard, 8-12 weeks aerospace custom.
Over thirty years in fastener manufacture with current ISO 9001:2015, AS9100D, PED, and NORSOK M-650 quality system audits.
Recent A286 Dowel Pins Order Patterns
Active dowel-pin orders cover ISO 8734 ⌀ 6 mm and ⌀ 8 mm h7 on aerospace accessory gearbox alignment, DIN 6325 ⌀ 10 mm m6 press-fit on automotive turbocharger housing alignment, NAS 1351-N0 1/8 inch on fighter-jet engine module alignment, and ⌀ 12 mm on stamping-press die alignment.
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