Product available Ships today (order by 14:00) CO2 GPSR PPWR REACH

MW 40x8 / N38 - cylindrical magnet

cylindrical magnet

Catalog no 010069

GTIN/EAN: 5906301810681

5.00
Load capacity 20.43 kg / 200.39 N Magnetic Induction 230.22 mT / 2302 Gs
Diameter Ø
40 mm [±0,1 mm]
Height
8 mm [±0,1 mm]
Weight
75.4 g
Magnetization Direction
↑ axial
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

25.42net / pcs

31.27 zł with VAT (23% VAT) / pcs

price for transport

bulk discounts:

Need more?

Quantity
Net
Gross
price from 1 pcs
25.42 zł
31.27 zł
price from 30 pcs
23.89 zł
29.39 zł
price from 100 pcs
22.37 zł
27.51 zł

Frequently asked questions

What is the maximum working temperature of a disc magnet?
Standard N-series grades work up to 80 °C. Grades N50, N52 and N54 have a lower limit of 60 °C, because coercivity falls as BHmax rises. Higher temperatures require the H (120 °C), SH (150 °C), UH (180 °C), EH (200 °C) or AH (230 °C) series. Within the working range the magnet loses about 0.11% of its induction per degree, and that loss is reversible.
What is the difference between N38, N42 and N52?
The number after N is the energy product BHmax. Moving from N38 to N52 raises it by several tens of percent, but the real holding force increases by roughly 20%, because force also depends on geometry and on the magnetic circuit. N52 costs about twice as much as N42, so for most mounting work N38–N42 is the best price-to-force ratio.
What is the dimensional tolerance?
±0.1 mm as standard, ±0.05 mm to order. The tolerance is stated next to the dimensions on every product page.

Engineering report for this magnet

Full PDF analysis: pull and shear force, effect of distance, temperature and plate thickness, safety distances and the demagnetization curve.

Want to talk magnets?

Call us now +48 888 99 98 98 alternatively let us know using contact form the contact section.
Specifications and structure of a neodymium magnet can be estimated using our power calculator.

Order by 14:00 and we’ll ship today!

Technical - MW 40x8 / N38 - cylindrical magnet

Specification / characteristics - MW 40x8 / N38 - cylindrical magnet

properties
properties values
Cat. no. 010069
GTIN/EAN 5906301810681
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
Diameter Ø 40 mm [±0,1 mm]
Height 8 mm [±0,1 mm]
Weight 75.4 g
Magnetization Direction ↑ axial
Load capacity ~ ? 20.43 kg / 200.39 N
Magnetic Induction ~ ? 230.22 mT / 2302 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MW 40x8 / N38 - cylindrical magnet
properties values units
Remanence Br ? 12.2-12.6 kGs
Remanence Br ? 1220-1260 mT
Coercivity bHc ? 10.8-11.5 kOe
Coercivity bHc ? 860-915 kA/m
Intrinsic coercivity iHc ≥ 12 kOe
Intrinsic coercivity iHc ≥ 955 kA/m
Energy product BHmax ? 36-38 BH max MGOe
Energy product BHmax ? 287-303 BH max KJ/m
Maximum working temperature ? ≤ 80 °C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C
properties values units
Vickers hardness ≥550 Hv
Density ≥7.4 g/cm3
Curie Temperature TC 310 °C
Curie Temperature TF 590 °F
Specific resistance 150 μΩ⋅cm
Bending strength 250 MPa
Compressive strength 1000~1100 MPa
Thermal expansion parallel (∥) to orientation (M) (3-4) x 10-6 °C-1
Thermal expansion perpendicular (⊥) to orientation (M) -(1-3) x 10-6 °C-1
Young's modulus 1.7 x 104 kg/mm²

Engineering modeling of the magnet - technical parameters

Presented values are the result of a mathematical simulation. Results are based on models for the material Nd2Fe14B. Operational performance may deviate from the simulation results. Treat these data as a preliminary roadmap when designing systems.

Table 1: Static force (force vs distance) - power drop
MW 40x8 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 2302 Gs
230.2 mT
20.43 kg / 45.04 LBS
20430.0 g / 200.4 N
dangerous!
1 mm 2235 Gs
223.5 mT
19.25 kg / 42.44 LBS
19252.0 g / 188.9 N
dangerous!
2 mm 2156 Gs
215.6 mT
17.92 kg / 39.50 LBS
17917.4 g / 175.8 N
dangerous!
3 mm 2068 Gs
206.8 mT
16.49 kg / 36.36 LBS
16490.6 g / 161.8 N
dangerous!
5 mm 1875 Gs
187.5 mT
13.56 kg / 29.89 LBS
13556.7 g / 133.0 N
dangerous!
10 mm 1375 Gs
137.5 mT
7.29 kg / 16.07 LBS
7287.4 g / 71.5 N
warning
15 mm 959 Gs
95.9 mT
3.54 kg / 7.81 LBS
3542.3 g / 34.8 N
warning
20 mm 661 Gs
66.1 mT
1.68 kg / 3.71 LBS
1684.9 g / 16.5 N
safe
30 mm 328 Gs
32.8 mT
0.41 kg / 0.91 LBS
414.2 g / 4.1 N
safe
50 mm 105 Gs
10.5 mT
0.04 kg / 0.09 LBS
42.3 g / 0.4 N
safe

Table 2: Vertical capacity (vertical surface)
MW 40x8 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 4.09 kg / 9.01 LBS
4086.0 g / 40.1 N
1 mm Stal (~0.2) 3.85 kg / 8.49 LBS
3850.0 g / 37.8 N
2 mm Stal (~0.2) 3.58 kg / 7.90 LBS
3584.0 g / 35.2 N
3 mm Stal (~0.2) 3.30 kg / 7.27 LBS
3298.0 g / 32.4 N
5 mm Stal (~0.2) 2.71 kg / 5.98 LBS
2712.0 g / 26.6 N
10 mm Stal (~0.2) 1.46 kg / 3.21 LBS
1458.0 g / 14.3 N
15 mm Stal (~0.2) 0.71 kg / 1.56 LBS
708.0 g / 6.9 N
20 mm Stal (~0.2) 0.34 kg / 0.74 LBS
336.0 g / 3.3 N
30 mm Stal (~0.2) 0.08 kg / 0.18 LBS
82.0 g / 0.8 N
50 mm Stal (~0.2) 0.01 kg / 0.02 LBS
8.0 g / 0.1 N

Table 3: Vertical assembly (sliding) - behavior on slippery surfaces
MW 40x8 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
6.13 kg / 13.51 LBS
6129.0 g / 60.1 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
4.09 kg / 9.01 LBS
4086.0 g / 40.1 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
2.04 kg / 4.50 LBS
2043.0 g / 20.0 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
10.22 kg / 22.52 LBS
10215.0 g / 100.2 N

Table 4: Steel thickness (substrate influence) - sheet metal selection
MW 40x8 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
5%
1.02 kg / 2.25 LBS
1021.5 g / 10.0 N
1 mm
13%
2.55 kg / 5.63 LBS
2553.8 g / 25.1 N
2 mm
25%
5.11 kg / 11.26 LBS
5107.5 g / 50.1 N
3 mm
38%
7.66 kg / 16.89 LBS
7661.3 g / 75.2 N
5 mm
63%
12.77 kg / 28.15 LBS
12768.8 g / 125.3 N
10 mm
100%
20.43 kg / 45.04 LBS
20430.0 g / 200.4 N
11 mm
100%
20.43 kg / 45.04 LBS
20430.0 g / 200.4 N
12 mm
100%
20.43 kg / 45.04 LBS
20430.0 g / 200.4 N

Table 5: Thermal stability (material behavior) - power drop
MW 40x8 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 20.43 kg / 45.04 LBS
20430.0 g / 200.4 N
OK
40 °C -2.2% 19.98 kg / 44.05 LBS
19980.5 g / 196.0 N
OK
60 °C -4.4% 19.53 kg / 43.06 LBS
19531.1 g / 191.6 N
80 °C -6.6% 19.08 kg / 42.07 LBS
19081.6 g / 187.2 N
100 °C -28.8% 14.55 kg / 32.07 LBS
14546.2 g / 142.7 N

Table 6: Two magnets (repulsion) - field collision
MW 40x8 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Shear Strength (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 41.05 kg / 90.51 LBS
3 871 Gs
6.16 kg / 13.58 LBS
6158 g / 60.4 N
N/A
1 mm 39.92 kg / 88.02 LBS
4 540 Gs
5.99 kg / 13.20 LBS
5989 g / 58.7 N
35.93 kg / 79.22 LBS
~0 Gs
2 mm 38.69 kg / 85.29 LBS
4 469 Gs
5.80 kg / 12.79 LBS
5803 g / 56.9 N
34.82 kg / 76.76 LBS
~0 Gs
3 mm 37.38 kg / 82.40 LBS
4 393 Gs
5.61 kg / 12.36 LBS
5606 g / 55.0 N
33.64 kg / 74.16 LBS
~0 Gs
5 mm 34.59 kg / 76.25 LBS
4 226 Gs
5.19 kg / 11.44 LBS
5188 g / 50.9 N
31.13 kg / 68.63 LBS
~0 Gs
10 mm 27.24 kg / 60.06 LBS
3 750 Gs
4.09 kg / 9.01 LBS
4086 g / 40.1 N
24.52 kg / 54.05 LBS
~0 Gs
20 mm 14.64 kg / 32.28 LBS
2 750 Gs
2.20 kg / 4.84 LBS
2197 g / 21.5 N
13.18 kg / 29.06 LBS
~0 Gs
50 mm 1.65 kg / 3.63 LBS
922 Gs
0.25 kg / 0.54 LBS
247 g / 2.4 N
1.48 kg / 3.26 LBS
~0 Gs
60 mm 0.83 kg / 1.84 LBS
656 Gs
0.12 kg / 0.28 LBS
125 g / 1.2 N
0.75 kg / 1.65 LBS
~0 Gs
70 mm 0.44 kg / 0.97 LBS
477 Gs
0.07 kg / 0.15 LBS
66 g / 0.6 N
0.40 kg / 0.87 LBS
~0 Gs
80 mm 0.24 kg / 0.54 LBS
355 Gs
0.04 kg / 0.08 LBS
37 g / 0.4 N
0.22 kg / 0.49 LBS
~0 Gs
90 mm 0.14 kg / 0.31 LBS
270 Gs
0.02 kg / 0.05 LBS
21 g / 0.2 N
0.13 kg / 0.28 LBS
~0 Gs
100 mm 0.09 kg / 0.19 LBS
210 Gs
0.01 kg / 0.03 LBS
13 g / 0.1 N
0.08 kg / 0.17 LBS
~0 Gs

Table 7: Protective zones (electronics) - precautionary measures
MW 40x8 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 15.5 cm
Hearing aid 10 Gs (1.0 mT) 12.5 cm
Timepiece 20 Gs (2.0 mT) 9.5 cm
Mobile device 40 Gs (4.0 mT) 7.5 cm
Car key 50 Gs (5.0 mT) 7.0 cm
Payment card 400 Gs (40.0 mT) 3.0 cm
HDD hard drive 600 Gs (60.0 mT) 2.5 cm

Table 8: Impact energy (kinetic energy) - warning
MW 40x8 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 21.48 km/h
(5.97 m/s)
1.34 J
30 mm 24.93 km/h
(6.93 m/s)
1.81 J
50 mm 25.14 km/h
(6.98 m/s)
1.84 J
100 mm 25.18 km/h
(6.99 m/s)
1.84 J

Table 9: Corrosion resistance
MW 40x8 / N38

Technical parameter Value / Description
Coating type [NiCuNi] Nickel
Layer structure Nickel - Copper - Nickel
Layer thickness 10-20 µm
Salt spray test (SST) ? 24 h
Recommended environment Indoors only (dry)

Table 10: Construction data (Pc)
MW 40x8 / N38

Parameter Value SI Unit / Description
Magnetic Flux 33 553 Mx 335.5 µWb
Pc Coefficient 0.29 Low (Flat)

Table 11: Hydrostatics and buoyancy
MW 40x8 / N38

Environment Effective steel pull Effect
Air (land) 20.43 kg Standard
Water (riverbed) 23.39 kg
(+2.96 kg buoyancy gain)
+14.5%
Warning: Standard nickel requires drying after every contact with moisture; lack of maintenance will lead to rust spots.

1. Wall mount (shear)

*Warning: On a vertical surface, the magnet retains merely a fraction of its nominal pull.

2. Steel thickness impact

*Thin steel (e.g. 0.5mm PC case) severely limits the holding force.

3. Thermal stability

*For N38 material, the safety limit is 80°C.

4. Demagnetization curve and operating point (B-H)

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 0.29

This simulation demonstrates the magnetic stability of the selected magnet under specific geometric conditions. The solid red line represents the demagnetization curve (material potential), while the dashed blue line is the load line based on the magnet's geometry. The Pc (Permeance Coefficient), also known as the load line slope, is a dimensionless value that describes the relationship between the magnet's shape and its magnetic stability. The intersection of these two lines (the black dot) is the operating point — it determines the actual magnetic flux density generated by the magnet in this specific configuration. A higher Pc value means the magnet is more 'slender' (tall relative to its area), resulting in a higher operating point and better resistance to irreversible demagnetization caused by external fields or temperature. A value of 0.42 is relatively low (typical for flat magnets), meaning the operating point is closer to the 'knee' of the curve — caution is advised when operating at temperatures near the maximum limit to avoid strength loss.

Technical and environmental data

Elemental analysis

iron (Fe) 64% – 68%
neodymium (Nd) 29% – 32%
boron (B) 1.1% – 1.2%
dysprosium (Dy) 0.5% – 2.0%
coating (Ni-Cu-Ni) < 0.05%

Sustainability

recyclability (EoL) 100%
recycled raw materials ~10% (pre-cons)
carbon footprint low / zredukowany
waste code (EWC) 16 02 16
Safety card (GPSR)
responsible entity
Dhit sp. z o.o.
ul. Kościuszki 6A, 05-850 Ożarów Mazowiecki
tel: +48 22 499 98 98 | e-mail: bok@dhit.pl
batch number/type
id: 010069-2026
Quick Unit Converter

Pulling force


Magnetic Induction

Other offers

This product is an exceptionally strong cylinder magnet, made from modern NdFeB material, which, at dimensions of Ø40x8 mm, guarantees the highest energy density. This specific item boasts an accuracy of ±0.1mm and industrial build quality, making it a perfect solution for professional engineers and designers. As a magnetic rod with impressive force (approx. 20.43 kg), this product is in stock from our European logistics center, ensuring rapid order fulfillment. Moreover, its Ni-Cu-Ni coating effectively protects it against corrosion in typical operating conditions, guaranteeing an aesthetic appearance and durability for years.
This model is perfect for building electric motors, advanced Hall effect sensors, and efficient filters, where maximum induction on a small surface counts. Thanks to the pull force of 200.39 N with a weight of only 75.4 g, this rod is indispensable in electronics and wherever low weight is crucial.
Since our magnets have a tolerance of ±0.1mm, the recommended way is to glue them into holes with a slightly larger diameter (e.g., 40.1 mm) using epoxy glues. To ensure long-term durability in industry, specialized industrial adhesives are used, which are safe for nickel and fill the gap, guaranteeing high repeatability of the connection.
Magnets NdFeB grade N38 are strong enough for 90% of applications in modeling and machine building, where extreme miniaturization with maximum force is not required. If you need the strongest magnets in the same volume (Ø40x8), contact us regarding higher grades (e.g., N50, N52), however, N38 is the standard in continuous sale in our warehouse.
This model is characterized by dimensions Ø40x8 mm, which, at a weight of 75.4 g, makes it an element with impressive magnetic energy density. The value of 200.39 N means that the magnet is capable of holding a weight many times exceeding its own mass of 75.4 g. The product has a [NiCuNi] coating, which protects the surface against external factors, giving it an aesthetic, silvery shine.
This rod magnet is magnetized axially (along the height of 8 mm), which means that the N and S poles are located on the flat, circular surfaces. Thanks to this, the magnet can be easily glued into a hole and achieve a strong field on the front surface. On request, we can also produce versions magnetized through the diameter if your project requires it.

Pros as well as cons of neodymium magnets.

Benefits

Besides their magnetic performance, neodymium magnets are valued for these benefits:
  • Their power remains stable, and after approximately ten years it decreases only by ~1% (according to research),
  • Neodymium magnets remain highly resistant to demagnetization caused by magnetic disturbances,
  • Thanks to the shiny finish, the coating of nickel, gold-plated, or silver-plated gives an professional appearance,
  • Magnetic induction on the top side of the magnet remains maximum,
  • Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures reaching 230°C and above...
  • Possibility of accurate shaping as well as adapting to defined needs,
  • Fundamental importance in modern industrial fields – they are used in mass storage devices, electromotive mechanisms, medical equipment, and other advanced devices.
  • Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in small systems

Limitations

Disadvantages of NdFeB magnets:
  • To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
  • NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
  • Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
  • We suggest cover - magnetic mount, due to difficulties in producing threads inside the magnet and complex shapes.
  • Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets can disrupt the diagnostic process medical after entering the body.
  • High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Holding force characteristics

Detachment force of the magnet in optimal conditionswhat contributes to it?

The force parameter is a measurement result performed under specific, ideal conditions:
  • using a sheet made of mild steel, functioning as a magnetic yoke
  • with a cross-section no less than 10 mm
  • with a surface cleaned and smooth
  • with direct contact (without paint)
  • for force applied at a right angle (pull-off, not shear)
  • at temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

In real-world applications, the actual lifting capacity depends on several key aspects, ranked from crucial:
  • Distance (betwixt the magnet and the plate), because even a microscopic clearance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to paint, corrosion or dirt).
  • Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
  • Base massiveness – insufficiently thick plate causes magnetic saturation, causing part of the power to be lost to the other side.
  • Steel type – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and holding force.
  • Plate texture – smooth surfaces guarantee perfect abutment, which increases force. Rough surfaces weaken the grip.
  • Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the holding force is lower. Moreover, even a slight gap between the magnet’s surface and the plate decreases the load capacity.

Warnings
Data carriers

Data protection: Neodymium magnets can ruin payment cards and delicate electronics (heart implants, hearing aids, timepieces).

Conscious usage

Use magnets with awareness. Their powerful strength can surprise even experienced users. Stay alert and respect their power.

Finger safety

Protect your hands. Two large magnets will join immediately with a force of massive weight, destroying everything in their path. Be careful!

Medical interference

Warning for patients: Strong magnetic fields affect electronics. Maintain at least 30 cm distance or request help to work with the magnets.

Warning for allergy sufferers

Certain individuals have a contact allergy to nickel, which is the common plating for NdFeB magnets. Extended handling can result in skin redness. We suggest use protective gloves.

Dust is flammable

Drilling and cutting of NdFeB material poses a fire risk. Neodymium dust reacts violently with oxygen and is hard to extinguish.

GPS Danger

Remember: rare earth magnets generate a field that disrupts precision electronics. Keep a separation from your mobile, device, and navigation systems.

Beware of splinters

Despite metallic appearance, the material is brittle and cannot withstand shocks. Avoid impacts, as the magnet may shatter into sharp, dangerous pieces.

Demagnetization risk

Do not overheat. Neodymium magnets are sensitive to temperature. If you require operation above 80°C, ask us about special high-temperature series (H, SH, UH).

Keep away from children

Neodymium magnets are not intended for children. Accidental ingestion of several magnets may result in them connecting inside the digestive tract, which poses a severe health hazard and necessitates urgent medical intervention.

Attention! Looking for details? Check our post: Why are neodymium magnets dangerous?