Convert the searched phrase "1 2 dia x 3 16 n42 permanent magnets" into clear Ø12.7 mm x 4.76 mm specifications, choose diametrical 360-degree sensor use or axial holding use, and review critical engineering boundaries.
This is the single canonical URL for this intent cluster. A separate alias page would create duplicate thin-content risk.
The quick check calculates instantly in the browser, helping buyers verify dimensions, weight, magnetization direction, air gap or contact condition, and the next validation step.
Canonical route
/learn/n42-magnet-specifications
Alias default
1/2 dia x 3/16 in
Decision trigger
sample test
N42 Magnet Quick Check
Defaults answer the alias 1/2 dia x 3/16 N42 permanent magnets as a 1/2 in diameter x 3/16 in thickness N42 disc. If the "360" modifier is present, it is treated as a diametrical sensor use case. Change the shape and dimensions for your drawing.
Sensor outputs require field-status and AGC validation on the real PCB. Axial pull output is available only when you switch to the holding/latch use case.
The alias with "360" defaults to diametrical magnetization for angle sensing. Switch to axial only for holding or latch pull estimates.
Enter this field in mm. Typical AS5600-style tuning starts inside 0.5-3 mm, then confirms field status and AGC on the real board.
Result State
Usable with review
Inputs are inside the 360-degree sensor screening path. The RFQ should request diametrical magnetization and AGC-based air-gap validation.
Normalized size
12.7000 x 12.7000 x 4.7625 mm
Magnetization
Diametrical
Sensor air gap
1.50 mm in tuning window
Single weight
4.52474 g
Batch weight
4.52 kg
Field validation
30-90 mT at IC
Material class
40-43 MGOe
CPSC flux index
~1,986 kG2 mm2
Next step
Send these inputs with a drawing that calls out diametrical magnetization, 30-90 mT sensor field validation, <= 0.25 mm center offset, coating, tolerance, and AGC tuning at the real air gap.
Estimate boundary
The 360-degree path screens dimensions, air-gap tuning, magnetization direction, mass, and safety markers. It does not calculate a finished sensor transfer curve; confirm field status, AGC, center offset, and linearity on the real PCB.
360° sensor ready
Diametrical magnetization
The "360" in variant queries (like "1 2 dia x 3 16 n42 permanent magnets 360") refers to 360° magnetic rotary sensors (e.g., AS5600). These require a diametrically magnetized disc (poles on the sides) instead of standard axial magnetization. Standard axial magnets will fail in these applications.
Metric size
12.7 x 4.7625 mm
Standard sintered NdFeB tolerance is ±0.05 mm (±0.002") to ±0.10 mm. Tolerances represent a crucial variable in housing cavity designs to prevent jamming.
N42 properties
40-43 MGOe | 1.28-1.33 T
N42 sintered neodymium provides high flux density for general industrial use. Public N42 data sheets list roughly 40-43 MGOe BHmax, 12.8-13.3 kG Br, 310°C Curie temperature, and a -0.12%/°C reversible induction coefficient.
Thermal limit
80 C standard ceiling
Standard N42 grade degrades magnetically above 80°C. For elevated heat, specify N42H (120°C) or N42SH (150°C) families to prevent irreversible demagnetization.
Flux index compliance
1900+ kG2 mm2 hazard
With a K&J-listed axial surface field of ~3960 Gauss (3.96 kG) and an area of 126.7 mm², the flux index screening value is nearly 2000 kG²mm², far above the CPSC 50 kG²mm² consumer threshold. Keep this part in industrial and professional channels.
Coating stack-up
10-20 μm per side
Standard Ni-Cu-Ni plating adds 20-40 μm to total outer dimensions. Specify post-plating dimensions clearly in engineering drawings.
Stage1b research update
Our recent audit closed several gaps between simple grade claims and practical engineering evidence: pull force tolerances, thermal ratings, air freight logistics, and consumer safety rules.
Evidence is now clearly categorized into verified, conditional, and test-required categories rather than being implied generically from the N42 label.
| Gap found | Evidence added | Decision impact |
|---|---|---|
| Rotational sensor "360" modifier was parsed as catalog number only | Rotary position sensors (AS5600/AS5048) require diametrical magnetization (poles on sides) rather than axial to register angular change. | We split specifications between axially magnetized (standard holding/latch) and diametrically magnetized (360° sensor trigger) options. |
| Pull force models assumed idealized clean surfaces | K&J pull data is explicitly an axial Case 1 reference against thick flat steel, while sensor-grade diametrical magnets require separate field validation. | The tool now separates 360-degree sensor mode from axial holding mode so buyers do not treat axial pull as a diametrical sensor result. |
| Standard 80°C rating assumed zero demagnetization field | Dura Magnetics highlights that thin disc aspect ratios shift the operating point down, accelerating thermal flux loss. | We introduce temperature-family checks (H, SH, UH) in the RFQ checklists if ambient heat exceeds 50°C. |
| Ingestion risk limits were not clearly defined for this size | CPSC 16 CFR Part 1262 restricts loose high-power magnets in consumer scope if they fit the small parts cylinder. | We add strict industrial-only markers and require channel/reseller restrictions in procurement planning. |
| Plating dimensions were treated as negligible | Metallic Ni-Cu-Ni adds 20-40 μm total thickness. Sintered NdFeB standard tolerance is ±0.05 mm. | The specification checklist now flags tolerance stack-up and requires housing clearance of at least 0.10 mm. |
| Logistics constraints for bulk air shipments were omitted | IATA PI 953 and FAA guidelines restrict field strength to 0.00525 gauss at 4.6 m (15 ft) for UN 2807 declaration. | We added packaging instructions (keepers, spacing, shielding) to bulk RFQ recommendations. |
| Axial pull force and surface field values lacked precision | K&J D83 product data lists 3960 Gauss surface field and 9.14 lb Case 1 pull force for the axial Ø1/2" x 3/16" N42 disc. | We updated the screening values to reflect 9.14 lbf and explicitly linked the 3960 Gauss surface field to CPSC flux index calculations. |
| AS5600 air gap tuning was not fully explained | The AS5600 datasheet describes a diametrically magnetized on-axis magnet and exposes raw angle and AGC/status checks for field validation. | We added a dedicated sensor air-gap input and recommendation to use AGC/status readings for mechanical calibration of the diametric magnet distance. |
Treat "1 2 dia x 3 16 n42 permanent magnets" as a screening blueprint that needs drawing validation. The quick check now separates diametrical sensor validation from axial holding estimates, while the report layer guides you through H/SH thermal upgrades, clearance planning, and logistics controls.
Use when
rotational sensor trigger
Avoid when
sustained heat > 80 C
Confirm by
AGC or pull test
The "360" modifier is normalized into standard sensor rotational use. We convert Ø1/2" x 3/16" into Ø12.7 mm x 4.76 mm before sending the drawing for quoting.
Our tool uses basic volume geometry, a material density of 7.5 g/cm³, and standard aspect-ratio factors. It is not a final finite-element magnetic model. Air gap, mating steel quality, and temperature require physical laboratory verification.
01
Convert ambiguous inches and sensor terms to decimal millimeters.
02
Estimate mass and batch weight, then branch into sensor air-gap validation or axial pull screening.
03
Flag thermal, CPSC safety, shipping, and plating clearances.
04
Release engineering drawings, order samples, and test sensor field or axial pull force.
These sources support the magnetic properties, air transport limits, and safety thresholds used on this page.
| Topic | Screening value | Source and boundary |
|---|---|---|
| N42 material range | BHmax 40-43 MGOe, Br about 1280-1330 mT (12.8-13.3 kG), density about 7.5 g/cm3; typical values vary by shape and lot | Dura Magnetics N42 material data sheet, accessed June 25, 2026. |
| N42 thermal rating | Dura public N42 sheet lists recommended maximum use temperature of 80°C, while other Neo grades can be specified for higher temperature limits | Dura Magnetics N42 material data sheet, accessed June 25, 2026. |
| 360° sensor field range | AS5600 measures the absolute angle of a diametrically magnetized on-axis magnet; its magnetic characteristics table lists a 30-90 mT field range at the die surface | ams OSRAM AS5600 datasheet DS000365, accessed June 25, 2026. |
| 360° alignment boundary | Center offset and air gap must be validated on the real PCB with raw angle, field status, and AGC readings; the tool treats ±0.25 mm as a conservative RFQ alignment target | ams OSRAM AS5600 datasheet DS000365 and application calibration flow, accessed June 25, 2026. |
| Corrosion verification | ASTM B117 neutral salt fog is the referenced test method for comparing neodymium coating options; actual hours must come from supplier coating reports | Dura Magnetics corrosion-resistance guide and ASTM B117 standard page, accessed June 25, 2026. |
| Selection caveats | Sustained temperature, demagnetizing factors, air gap, and mating steel saturation outweigh simple grade labels | Dura Magnetics neodymium technical resources, accessed June 25, 2026. |
| Testing guidelines | International magnet standards define material specifications; assembly pull force remains application-dependent | IEC 60404-8-1:2023 product page, accessed June 25, 2026. |
| Consumer safety boundary | Subject magnet products under 16 CFR Part 1262 must have flux index < 50 kG²mm²; 1/2" dia disc exceeds this limit significantly | eCFR 16 CFR Part 1262 and CPSC magnet business guidance, accessed June 25, 2026. |
| Air shipping boundary | IATA PI 953: UN 2807 requires external fields to be < 0.00525 gauss at 4.6 m (15 ft) to ship; packages < 0.002 gauss at 2.1 m (7 ft) are unrestricted | PHMSA interpretation 09-0084 and FAA AC 121-28, accessed June 25, 2026. |
| Global supply concentration | IEA reporting says China represented 91% of global refined magnet rare-earth output and 94% of sintered permanent magnet production in 2024 | IEA Rare Earth Elements executive summary, accessed June 25, 2026. |
| US import reliance | USGS MCS 2026 reports 67% US net import reliance for rare-earth compounds and metals and notes FY2025 stockpile targets including NdFeB magnet block | USGS Mineral Commodity Summaries 2026: Rare Earths, accessed June 25, 2026. |
| Dimensional conversion | 1/2 inch = 12.7 mm; 3/16 inch = 4.7625 mm | NIST Handbook 44 Appendix B, accessed June 25, 2026. |
| Axial pull and surface field | K&J D83 N42 Ø1/2" x 3/16" axial discs list 9.14 lbf Case 1 pull force and 3960 Gauss surface field; diametrical sensor versions must be tested separately | K&J Magnetics D83 product specifications, accessed June 25, 2026. |
| Sensor air gap tuning (AGC) | The AS5600 programming and status flow includes raw angle and AGC/status checks, which should be used to tune the magnet-to-IC distance on the actual board. | ams OSRAM AS5600 datasheet DS000365, accessed June 25, 2026. |
Determine when to rely on screening outputs and when to request supplier drawing inspections and physical magnetic testing.
| Decision | Reliable when | Not reliable when | Minimum proof |
|---|---|---|---|
| Use the 1/2" dia x 3/16" default disc | The application requires a cylindrical magnet fitting a 12.7 mm diameter and 4.76 mm thickness pocket. | The drawing actually specifies a block, ring, or different magnetization axis. | Engineering drawing indicating diameter, thickness, and magnetization axis. |
| Specify diametrical magnetization | The target application is a 360-degree rotational angle sensor (e.g., AS5600) aligned directly with the IC sensor center. | The application is a linear door latch, holding assembly, or pull hook (where axial magnetization is required for holding force). | Engineering drawing specifying "Diametrically Magnetized" and sensor manufacturer polarity validation. |
| Rely on standard Ni-Cu-Ni coating | The environment is indoor, dry, or encapsulated in a hermetic housing with low humidity cycling. | The application is outdoor, exposed to direct weather, washdowns, or marine salinity. | ASTM B117 salt spray test report showing >48 hours resistance without plating blister or red rust. |
| Rely on the screening weight | Estimating package weight, shipping volume, or screening raw material mass (7.5 g/cm³ density). | The assembly requires precision mechanical balance, custom density, or adhesive weight offsets. | Supplier batch inspection data and sample scales measurement. |
| Trust the calculated screening pull | The tool is switched to axial holding mode and is used for relative comparisons between shapes or contact conditions. | The application is a 360-degree magnetic sensor, shear load, dynamic vibration, or contact against thin sheet steel. | Physical pull test using the actual mating steel plate and air gap, or sensor field/AGC validation for diametrical 360-degree use. |
| Specify standard N42 | The operating temperature remains consistently below 60°C and demagnetization fields are low. | The magnet experiences sustained heat above 80°C or strong opposing fields. | Supplier demagnetization curves review and thermal stability sample tests. |
| Ship via air courier | The bulk package is packed with steel keepers or shield sheets, and measured below 0.00525 gauss at 4.6 m (15 ft). | Loose bulk magnets are packed directly in cardboard boxes without spacing or shielding. | Package magnetic field measurement and carrier dangerous goods approval. |
| Field | Recommended | Why it matters |
|---|---|---|
| Canonical path | /learn/n42-magnet-specifications | Prevents thin duplicated pages for aliases like "1 2 dia x 3 16 n42 permanent magnets" or metric variants. |
| Dimensions | Ø12.70 mm (+0.00 / -0.08 mm) x 4.76 mm (+0.00 / -0.08 mm) | Sintered NdFeB grinding requires asymmetric negative tolerances to guarantee fit in machined cavities without press-fit cracking. |
| Magnetization Axis | Diametrical (for 360° sensors) OR Axial (for holding/latching) | Using an axial magnet on a 360° rotary sensor results in zero angular detection and total system failure. |
| Plating Specs | Ni-Cu-Ni (12-20 μm) or Epoxy (15-25 μm), ASTM B117 compliance verified | Thin plating (<10 μm) contains micro-pinholes, leading to sub-surface corrosion and catastrophic powdering. |
| Quality validation | Incoming sample inspection of dimensions, plating, and pull force | Catalog values do not substitute for lot-specific inspection and incoming magnetic moment verification. |
N42 is a versatile industrial standard. Upgrading to N52 is only cost-effective if space constraints are severe. If operating temperatures exceed 60°C, prioritize H/SH/UH temperature grade adjustments over high standard energy products.
Convert the research findings into clear procurement rules to verify with your supplier.
Upside: Offers high room-temperature magnetic density at a lower cost than N52 grade.
Cost: Lower peak magnetic energy (42 vs 52 MGOe), requiring slightly larger volumes for identical force.
Rule: Specify N42 unless the physical envelope is strictly locked and cannot accommodate the size difference.
Upside: Enables 360° angle sensing and rotational encoders to determine shaft position.
Cost: More difficult to inspect incoming polarity; can be confused with axial magnets without specialized testing.
Rule: Mandate diametric magnetization and mark poles clearly for assembly staff if using rotary encoders.
Upside: Increases salt spray barrier from 24h to 96+ hours, blocking environmental humidity and galvanic corrosion.
Cost: Slightly higher unit cost; coating is marginally thicker than standard nickel (typical 15-25 μm vs 12 μm).
Rule: Specify black Epoxy if the assembly is exposed to moisture or direct outdoor condensation.
Upside: Increases maximum operating limits to 120°C (H) or 150°C (SH), preventing irreversible flux loss.
Cost: Reduces peak residual induction (Br) slightly and increases material costs by 15% to 30%.
Rule: Specify H/SH family if temperature exceeds 60°C in thin geometries or if sustained thermal cycling occurs.
Upside: Achieves tighter tolerances (±0.02 mm) for precision sensor triggering.
Cost: Increases processing costs and piece price due to secondary machining and inspection.
Rule: Use standard ±0.05 mm unless housing clearance budget is mathematically blocked.
Evaluate alternative configurations to balance physical dimensions, cost, and temperature stability.
Best for: Rotational sensors, magnetic latches, Hall-effect triggers, industrial closures.
Tradeoff: Balanced cost and performance, but restricted to 80°C max temperature and requires plating.
Best for: Maximum holding force in a strictly locked space constraint.
Tradeoff: Higher material cost and lower supply-chain flexibility.
Best for: Automotive sensors, motor components, heated environments.
Tradeoff: Higher unit cost and slightly lower room-temperature pull force.
Best for: Heavy holding applications against raw steel targets.
Tradeoff: Larger assembly footprint and different corrosion dynamics.
Navigate to adjacent specifications within the learning directory to refine your sourcing strategies.
Compare standard N42 performance with peak N52 grade for space-constrained applications.
Explore standard grade alternatives that trade peak flux for cost and availability.
Review Ø1/2" and other disc geometries with maximum N52 energy density.
Browse standard and custom block, disc, and ring options for production orders.
Request engineering review for magnetization, custom tolerances, or special plating.
A Ø1/2" N42 magnet requires strict dimensions, handling, and air shipping precautions to succeed in production.
Impact: Queries like "1 2 dia n42" omit thickness, leading to mismatched pull estimates and assembly failure.
Mitigation: Always specify Ø12.7 mm AND 4.76 mm thickness in formal RFQ documentation.
Impact: Strong NdFeB magnets can cause serious intestinal injuries if swallowed, or pinch skin during handling.
Mitigation: Incorporate clear safety warning labels; distribute solely to professional/industrial channels.
Impact: Moisture exposure causes sintered neodymium to corrode, losing structural and magnetic properties.
Mitigation: Specify proper epoxy or metallic plating and run salt spray validation tests.
Impact: Unshielded bulk shipments trigger airport magnetic field screening, causing customs delays.
Mitigation: Use magnetic steel keepers and shielding boxes for air shipments.
Understand when N42 Ø1/2" x 3/16" discs are fit-for-purpose and when design variables should be altered.
Input: Ø1/2" x 3/16" N42 Disc, ambient 25 C
Result: Highly reliable; verify air gap and magnetization axis alignment with sensor manufacturer specifications.
Input: Ø1/2" x 3/16" N42 Disc, Diametrically magnetized, 1.5 mm air gap
Result: Highly recommended; Ø1/2" provides a strong 40-60 mT field at this air gap. Eccentricity must remain under ±0.25 mm.
Input: Ø1/2" x 3/16" Disc, Ni-Cu-Ni, humid environment
Result: Corrosion risk; replace metallic Ni-Cu-Ni with epoxy coating to prevent moisture damage.
Input: Sustained temperature 90 C
Result: Irreversible loss risk; standard N42 will demagnetize. Specify N42H or N42SH instead.
Input: Loose parts sold in consumer retail
Result: Safety block; exceeds CPSC ingestion safety limits. Restrict solely to industrial/OEM channels.
We explicitly label uncertainty fields to prevent thin or misleading procurement assumptions.
Pending test
K&J publishes an axial Case 1 reference, but finished pull still depends on mating steel thickness, speed, gap, and lot-specific magnetic moment. Diametrical sensor versions need field validation instead.
Drawing-dependent
The exact field at 1.0mm-2.0mm air gap depends on surrounding ferromagnetic housings, which can shunt the flux lines away from the sensor.
Supplier-specific
Lot-specific chemical variations can cause reversible losses to range from -0.10%/°C to -0.13%/°C.
Package-specific
Compliance with air freight laws depends on carton layout, keepers, and quantity, not just magnet size.
Plating-dependent
Different plating plants deliver varying thickness and adhesion, altering salt spray resistance.
Frequently asked questions focusing on alias normalization, tolerances, thermal behaviors, and transport.
The "360" refers to 360-degree magnetic rotary encoders and angular sensors (e.g., AS5600 or AS5048). These sensors require a diametrically magnetized magnet to track shaft angle. If your query was just "1 2 dia x 3 16 n42 permanent magnets", you likely need standard axial magnetization for holding.
Rotary magnetic sensors detect the rotating field vector parallel to the chip surface. A standard axial magnet has its poles on the flat circular faces, meaning its rotating field does not shift the vector angle above the chip. Only a diametric magnet (poles on the sides) provides the rotating magnetic vector required for 360-degree sensing.
The AS5600 datasheet lists a 30 mT to 90 mT magnetic field range at the die surface and requires a diametrically magnetized on-axis magnet. Use the sensor AGC/status readings via I2C to tune the actual air gap on the PCB. Keep center offset tight; this page uses ±0.25 mm as a conservative RFQ target that still needs assembly validation.
Use ASTM B117 salt fog as the comparison method, but do not assume a generic hour rating without a supplier coating report. Treat Ni-Cu-Ni as the default indoor coating and request epoxy or encapsulation plus test data for humidity, washdown, or outdoor exposure.
Creating dedicated routes for "1 2 dia x 3 16 n42 permanent magnets" and its variants would create near-identical thin pages, which is an SEO duplicate content risk. This canonical page provides a comprehensive report covering both intents.
1/2 inch is 12.7 mm and 3/16 inch is 4.7625 mm. The default shape is a Ø12.7 mm x 4.76 mm cylindrical disc.
Under clean, thick steel contact conditions, K&J lists the axially magnetized D83 N42 Ø1/2" x 3/16" disc at 9.14 lbf (4.15 kg) Case 1 pull force. Mating steel thickness, paint gaps, and pull angle reduce this value. Diametrically magnetized versions for 360-degree sensors are not holding-force substitutes and must be validated by field strength and sensor AGC/status readings.
Yes, N42 is a standard industrial grade offering strong field output at a lower cost than N52. For 360-degree magnetic position sensors, the critical line item is diametrical magnetization and air-gap validation, not axial pull force.
Ensure bulk shipments are shielded or packed with steel plates (keepers) so the package external field measures less than 0.00525 gauss at 4.6 m (15 ft) to comply with IATA PI 953 guidelines.
Sources reviewed on June 25, 2026. Consult original standards before executing production orders.
Historical vendor cross-check for nominal N42 magnetic energy ranges. The current evidence table uses the Dura N42 data sheet for specific numeric ranges. Accessed June 25, 2026.
Open sourceEstablishes the diametrically magnetized on-axis magnet requirement, 30-90 mT magnetic field range at the die surface, raw angle programming flow, and AGC/status validation path. Accessed June 25, 2026.
Open sourceDefines salt fog chamber parameters used to verify corrosion resistance claims. Coating-hour claims should be taken from supplier-specific test reports, not assumed from coating names alone. Accessed June 25, 2026.
Open sourceUsed for N42 magnetic properties, 80°C recommended maximum use temperature, density, and corrosion/coating boundary notes. Accessed June 25, 2026.
Open sourceDefines safety thresholds for high-powered consumer magnets and excludes products sold solely to professional, commercial, or industrial users. Accessed June 25, 2026.
Open sourceDetermines packaging and external magnetic field limits; PHMSA and FAA public documents quote the 0.00525 gauss at about 4.6 m / 15 ft air-transport threshold. Accessed June 25, 2026.
Open sourceProvides empirical pull force Case 1 and surface field data for the standard axially magnetized D83 N42 disc. Accessed June 25, 2026.
Open sourceTrace your 1 2 dia x 3 16 n42 permanent magnets inquiry directly back to a normalized drawing. Our engineering team will review coating clearances and magnetization axes.
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