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MW 4x8 / N38 - cylindrical magnet

cylindrical magnet

Catalog no 010079

GTIN: 5906301810780

5.00

Diameter Ø

4 mm [±0,1 mm]

Height

8 mm [±0,1 mm]

Weight

0.75 g

Magnetization Direction

↑ axial

Load capacity

0.35 kg / 3.48 N

Magnetic Induction

599.59 mT / 5996 Gs

Coating

[NiCuNi] Nickel

0.701 ZŁ with VAT / pcs + price for transport

0.570 ZŁ net + 23% VAT / pcs

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MW 4x8 / N38 - cylindrical magnet

Specification / characteristics MW 4x8 / N38 - cylindrical magnet

properties

properties	values
Cat. no.	010079
GTIN	5906301810780
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	4 mm [±0,1 mm]
Height	8 mm [±0,1 mm]
Weight	0.75 g
Magnetization Direction	↑ axial
Load capacity ~ ?	0.35 kg / 3.48 N
Magnetic Induction ~ ?	599.59 mT / 5996 Gs
Coating	[NiCuNi] Nickel
Manufacturing Tolerance	±0.1 mm

Magnetic properties of material N38

Specification / characteristics MW 4x8 / N38 - cylindrical magnet

properties	values	units
remenance Br [Min. - Max.] ?	12.2-12.6	kGs
remenance Br [Min. - Max.] ?	1220-1260	T
coercivity bHc ?	10.8-11.5	kOe
coercivity bHc ?	860-915	kA/m
actual internal force iHc	≥ 12	kOe
actual internal force iHc	≥ 955	kA/m
energy density [Min. - Max.] ?	36-38	BH max MGOe
energy density [Min. - Max.] ?	287-303	BH max KJ/m
max. temperature ?	≤ 80	°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	312 - 380	°C
Curie Temperature TF	593 - 716	°F
Specific resistance	150	μΩ⋅Cm
Bending strength	250	Mpa
Compressive strength	1000~1100	Mpa
Thermal expansion parallel (∥) to orientation (M)	(3-4) x 106	°C^-1
Thermal expansion perpendicular (⊥) to orientation (M)	-(1-3) x 10-6	°C^-1
Young's modulus	1.7 x 104	kg/mm²

Physical analysis of the product - data

Presented data constitute the outcome of a physical calculation. Values were calculated on models for the class NdFeB. Operational parameters may differ from theoretical values. Treat these data as a preliminary roadmap for designers.

Table 1: Static pull force (force vs distance) - interaction chart
MW 4x8 / N38

Distance (mm)	Induction (Gauss) / mT	Pull Force (kg)	Risk Status
0 mm	5984 Gs 598.4 mT	0.35 kg / 350.0 g 3.4 N	weak grip
1 mm	3280 Gs 328.0 mT	0.11 kg / 105.1 g 1.0 N	weak grip
2 mm	1696 Gs 169.6 mT	0.03 kg / 28.1 g 0.3 N	weak grip
3 mm	941 Gs 94.1 mT	0.01 kg / 8.7 g 0.1 N	weak grip
5 mm	371 Gs 37.1 mT	0.00 kg / 1.3 g 0.0 N	weak grip
10 mm	82 Gs 8.2 mT	0.00 kg / 0.1 g 0.0 N	weak grip
15 mm	31 Gs 3.1 mT	0.00 kg / 0.0 g 0.0 N	weak grip
20 mm	15 Gs 1.5 mT	0.00 kg / 0.0 g 0.0 N	weak grip
30 mm	5 Gs 0.5 mT	0.00 kg / 0.0 g 0.0 N	weak grip
50 mm	1 Gs 0.1 mT	0.00 kg / 0.0 g 0.0 N	weak grip

Magnetic force decreases drastically per each millimeter of distance. Note that even the smallest gap (e.g., dirt, varnish, veneer) strongly diminishes the holding power. Magnetic products work strongest at the point of direct contact; gap nullifies the power. Observe how flashily the load capacity drop, when the magnet does not adhere directly to the steel surface. When designing the arrangement, avoid additional spacers.

Table 2: Vertical Hold (Wall)
MW 4x8 / N38

Distance (mm)	Friction coefficient	Pull Force (kg)
0 mm	Stal (~0.2)	0.07 kg / 70.0 g 0.7 N
1 mm	Stal (~0.2)	0.02 kg / 22.0 g 0.2 N
2 mm	Stal (~0.2)	0.01 kg / 6.0 g 0.1 N
3 mm	Stal (~0.2)	0.00 kg / 2.0 g 0.0 N
5 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N
10 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N
15 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N
20 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N
30 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N
50 mm	Stal (~0.2)	0.00 kg / 0.0 g 0.0 N

This section indicates the approximate shear load required to start the downward movement of the magnet vertically on a vertical steel wall (considering standard friction). This parameter depends on the distance between the magnet and the metal.

Table 3: Vertical assembly (shearing) - behavior on slippery surfaces
MW 4x8 / N38

Surface type	Friction coefficient / % Mocy	Max load (kg)
Raw steel	µ = 0.3 30% Nominalnej Siły	0.11 kg / 105.0 g 1.0 N
Painted steel (standard)	µ = 0.2 20% Nominalnej Siły	0.07 kg / 70.0 g 0.7 N
Oily/slippery steel	µ = 0.1 10% Nominalnej Siły	0.03 kg / 35.0 g 0.3 N
Magnet with anti-slip rubber	µ = 0.5 50% Nominalnej Siły	0.18 kg / 175.0 g 1.7 N

When placing a element on a upright wall (e.g., a car body), it will maintain barely approx. 1/5 of its maximum pull force. Gravity as well as a weak degree of grip cause that magnets move down easier than they pop off the substrate. Planning a vertical fastening? Note that the sliding force is noticeably lower than the perpendicular breakaway force. On a painted metal, the magnet will give way down under a much lighter load. Using a rubber layer can effectively improve the result.

Table 4: Steel thickness (substrate influence) - power losses
MW 4x8 / N38

Steel thickness (mm)	% power	Real pull force (kg)
0.5 mm	10%	0.03 kg / 35.0 g 0.3 N
1 mm	25%	0.09 kg / 87.5 g 0.9 N
2 mm	50%	0.18 kg / 175.0 g 1.7 N
5 mm	100%	0.35 kg / 350.0 g 3.4 N
10 mm	100%	0.35 kg / 350.0 g 3.4 N

A thin metal plate is unable to conduct the entire magnetic field, which squanders power of the magnet. Should you install a neodymium to a too thin substrate, the magnetism will pass right through and the pull force will drop sharply. To squeeze full efficiency of this magnet's power, you require a sufficiently solid backing of metal. The saturation effect means that on sheet metal structures (e.g., thin profiles), the product shows lower pull force. We recommend selecting the steel dimension from these parameters.

Table 5: Working in heat (material behavior) - thermal limit
MW 4x8 / N38

Ambient temp. (°C)	Power loss	Remaining pull	Status
20 °C	0.0%	0.35 kg / 350.0 g 3.4 N	OK
40 °C	-2.2%	0.34 kg / 342.3 g 3.4 N	OK
60 °C	-4.4%	0.33 kg / 334.6 g 3.3 N	OK
80 °C	-6.6%	0.33 kg / 326.9 g 3.2 N
100 °C	-28.8%	0.25 kg / 249.2 g 2.4 N

Standard neodymium magnets lose power past the thermal threshold. Protect against heat – heat can permanently demagnetize this product. With increasing heat, the neodymium's force temporarily decreases. Avoid using this magnet near heat sources higher than its working range. Exceeding the critical threshold will lead to permanent loss of magnetic properties.

*Engineering note: Temperature resistance is determined by both grade, but also on the magnet's shape. Low-profile magnets (low permeance coefficient) risk losing magnetic properties at lower temperatures compared to rod magnets. Red status in the table signals a risk of irreversible loss for this specific geometry.

Table 6: Two magnets (repulsion) - field collision
MW 4x8 / N38

Gap (mm)	Attraction (kg) (N-S)	Repulsion (kg) (N-N)
0 mm	2.77 kg / 2774 g 27.2 N 6 121 Gs	N/A
1 mm	1.59 kg / 1591 g 15.6 N 9 063 Gs	1.43 kg / 1432 g 14.0 N ~0 Gs
2 mm	0.83 kg / 833 g 8.2 N 6 559 Gs	0.75 kg / 750 g 7.4 N ~0 Gs
3 mm	0.43 kg / 427 g 4.2 N 4 694 Gs	0.38 kg / 384 g 3.8 N ~0 Gs
5 mm	0.12 kg / 121 g 1.2 N 2 498 Gs	0.11 kg / 109 g 1.1 N ~0 Gs
10 mm	0.01 kg / 11 g 0.1 N 743 Gs	0.01 kg / 10 g 0.1 N ~0 Gs
20 mm	0.00 kg / 1 g 0.0 N 165 Gs	0.00 kg / 0 g 0.0 N ~0 Gs
50 mm	0.00 kg / 0 g 0.0 N 17 Gs	0.00 kg / 0 g 0.0 N ~0 Gs

Two magnets attract each other from a significantly greater distance than a magnet and sheet setup. The setup of two magnets generates a stronger field and a wider radius of action. Designing a strong closure? Apply two magnets instead of a neodymium and a striker plate. Exercise caution that when connecting a pair of magnets, the collision energy is extreme. The levitation is a bit weaker than the attraction, but still impressive.
*Flux density for N-N configuration is approximately ~0 Gs at the midpoint of the gap (resulting from vector opposition).

Table 7: Protective zones (electronics) - precautionary measures
MW 4x8 / N38

Object / Device	Limit (Gauss) / mT	Safe distance
Pacemaker	5 Gs (0.5 mT)	3.5 cm
Hearing aid	10 Gs (1.0 mT)	2.5 cm
Timepiece	20 Gs (2.0 mT)	2.0 cm
Phone / Smartphone	40 Gs (4.0 mT)	1.5 cm
Remote	50 Gs (5.0 mT)	1.5 cm
Payment card	400 Gs (40.0 mT)	0.5 cm
HDD hard drive	600 Gs (60.0 mT)	0.5 cm

A strong magnetic field poses a large risk to electronic devices as well as medical implants. These neodymiums generate a field that disrupts operation of sensitive medical devices. Be aware: the unseen radiation passes through tissues and plastic. Exceptional care must be taken by people with cochlear implants and drug dispensers. The risk also applies to: mechanical watches, remotes, speakers, and displays. Do not bring the product near payment cards, HDD media, or sensitive navigation tools.

Table 8: Impact energy (cracking risk) - warning
MW 4x8 / N38

Start from (mm)	Speed (km/h)	Energy (J)
10 mm	21.79 km/h (6.05 m/s)	0.01 J
30 mm	37.74 km/h (10.48 m/s)	0.04 J
50 mm	48.72 km/h (13.53 m/s)	0.07 J
100 mm	68.89 km/h (19.14 m/s)	0.14 J

NdFeB products are very brittle – a collision with steel can result in shattering. Control the attraction moment – a magnet released freely turns into a projectile. Kinetic force can destroy the magnet or dangerous crushing to fingers. Be sure to control the product during bringing near metal so it doesn't slam with momentum against the steel surface. A collision at high speed means shattering of the neodymium. Wear eye protection when working with powerful specimens.

Table 9: Corrosion resistance
MW 4x8 / 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)

The SST (salt spray test) is an industry standard for determining coating lifespan in harsh conditions. Improper coating selection is the most common cause of magnet failure over time.

Table 10: Electrical data (Pc)
MW 4x8 / N38

Parameter	Value	Jedn. SI / Opis
Strumień (Flux)	836 Mx	8.4 µWb
Współczynnik Pc	1.21	Wysoki (Stabilny)

Flux value emitted by the magnet pole. Key data for generator builders and Hall effect devices. Permeance Coefficient defines the working geometry.

Table 11: Physics of underwater searching
MW 4x8 / N38

Environment	Effective steel pull	Effect
Air (land)	0.35 kg	Standard
Water (riverbed)	0.40 kg (+0.05 kg Buoyancy gain)	+14.5%

Warning: This magnet has a standard nickel coating. After use in water, it must be dried and maintained immediately, otherwise it will rust!

The magnetic field penetrates through water without any losses. Note: for permanent underwater work, we recommend magnets with an anti-corrosive (epoxy) coating.

1. Shear force

*Note: On a vertical surface, the magnet holds merely ~20% of its max power.

2. Steel saturation

*Thin steel (e.g. computer case) severely limits the holding force.

3. Temperature resistance

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

Quick Unit Converter

Force (Pull)

Force in kg

Newtons (N)

Pounds (lbs)

Field Strength

Tesla (T)

Put your value in just one field to see the conversion for all other fields immediately.

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This product is a very strong cylindrical magnet, composed of advanced NdFeB material, which, at dimensions of Ø4x8 mm, guarantees maximum efficiency. The MW 4x8 / N38 model is characterized by high dimensional repeatability and industrial build quality, making it an ideal solution for the most demanding engineers and designers. As a cylindrical magnet with significant force (approx. 0.35 kg), this product is available off-the-shelf from our warehouse in Poland, ensuring rapid order fulfillment. Moreover, its triple-layer Ni-Cu-Ni coating secures it against corrosion in standard operating conditions, ensuring an aesthetic appearance and durability for years.

It finds application in modeling, advanced automation, and broadly understood industry, serving as a fastening or actuating element. Thanks to the pull force of 3.48 N with a weight of only 0.75 g, this cylindrical magnet is indispensable in miniature devices and wherever every gram matters.

Due to the delicate structure of the ceramic sinter, we absolutely advise against force-fitting (so-called press-fit), as this risks chipping the coating of this professional component. To ensure stability in industry, anaerobic resins are used, which do not react with the nickel coating and fill the gap, guaranteeing durability of the connection.

Grade N38 is the most popular standard for industrial neodymium magnets, offering an optimal price-to-power ratio and high resistance to demagnetization. If you need the strongest magnets in the same volume (Ø4x8), contact us regarding higher grades (e.g., N50, N52), however, N38 is the standard available off-the-shelf in our warehouse.

This model is characterized by dimensions Ø4x8 mm, which, at a weight of 0.75 g, makes it an element with impressive magnetic energy density. The key parameter here is the lifting capacity amounting to approximately 0.35 kg (force ~3.48 N), which, with such defined dimensions, proves the high grade of the NdFeB material. 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. Such an arrangement is standard when connecting magnets in stacks (e.g., in filters) or when mounting in sockets at the bottom of a hole. On request, we can also produce versions magnetized through the diameter if your project requires it.

Strengths and weaknesses of rare earth magnets.

Benefits

Besides their immense magnetic power, neodymium magnets offer the following advantages:

Their strength remains stable, and after around ten years it drops only by ~1% (theoretically),
Neodymium magnets are extremely resistant to loss of magnetic properties caused by external field sources,
In other words, due to the shiny surface of silver, the element becomes visually attractive,
The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
Possibility of accurate machining and adapting to individual applications,
Key role in modern technologies – they are commonly used in data components, electric drive systems, medical equipment, also complex engineering applications.
Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages

Disadvantages of neodymium magnets:

At strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
Limited possibility of producing threads in the magnet and complicated forms - recommended is a housing - magnetic holder.
Possible danger resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, small elements of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
Due to expensive raw materials, their price exceeds standard values,

Pull force analysis

Maximum lifting capacity of the magnet – what it depends on?

The declared magnet strength concerns the peak performance, measured under optimal environment, specifically:

using a plate made of high-permeability steel, serving as a magnetic yoke
possessing a massiveness of at least 10 mm to avoid saturation
with a surface cleaned and smooth
without any air gap between the magnet and steel
for force acting at a right angle (pull-off, not shear)
at ambient temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

It is worth knowing that the application force may be lower depending on elements below, in order of importance:

Clearance – existence of foreign body (rust, dirt, gap) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of nominal force).
Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
Surface finish – ideal contact is possible only on polished steel. Rough texture create air cushions, reducing force.
Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

Lifting capacity was assessed using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, however under shearing force the lifting capacity is smaller. Moreover, even a small distance between the magnet and the plate lowers the lifting capacity.

Safe handling of neodymium magnets

Mechanical processing

Machining of neodymium magnets carries a risk of fire risk. Magnetic powder reacts violently with oxygen and is hard to extinguish.

Power loss in heat

Control the heat. Exposing the magnet to high heat will permanently weaken its properties and strength.

Allergy Warning

It is widely known that the nickel plating (standard magnet coating) is a common allergen. If you have an allergy, prevent touching magnets with bare hands or opt for versions in plastic housing.

Magnetic interference

Navigation devices and mobile phones are highly susceptible to magnetic fields. Direct contact with a strong magnet can decalibrate the internal compass in your phone.

Finger safety

Large magnets can break fingers in a fraction of a second. Never place your hand between two attracting surfaces.

Handling rules

Use magnets with awareness. Their powerful strength can surprise even professionals. Stay alert and do not underestimate their power.

Threat to electronics

Avoid bringing magnets close to a wallet, computer, or TV. The magnetic field can destroy these devices and wipe information from cards.

Health Danger

Warning for patients: Powerful magnets affect medical devices. Keep at least 30 cm distance or ask another person to work with the magnets.

Eye protection

NdFeB magnets are sintered ceramics, which means they are very brittle. Clashing of two magnets will cause them breaking into shards.

No play value

Absolutely keep magnets away from children. Choking hazard is significant, and the effects of magnets clamping inside the body are fatal.

Security! Looking for details? Read our article: Why are neodymium magnets dangerous?

MW 4x8 / N38 - cylindrical magnet

Want to talk magnets?

MW 4x8 / N38 - cylindrical magnet

Magnetic properties of material N38

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical analysis of the product - data

1. Shear force

2. Steel saturation

3. Temperature resistance

Force (Pull)

Field Strength

Other proposals

UMGW 48x24x11.5 [M8] GW / N38 - magnetic holder internal thread

UMP 94x40 [3xM10] GW F550 Silver Black Lina / N52 - search holder

MW 6x1 / N38 - cylindrical magnet

SM 32x250 [2xM8] / N42 - magnetic separator

Strengths and weaknesses of rare earth magnets.

Benefits

Disadvantages

Pull force analysis

Maximum lifting capacity of the magnet – what it depends on?

What influences lifting capacity in practice

Mechanical processing

Power loss in heat

Allergy Warning

Magnetic interference

Finger safety

Handling rules

Threat to electronics

Health Danger

Eye protection

No play value

Physical properties of sintered neodymium magnets Nd₂Fe₁₄B at 20°C