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MW 8x20 / N38 - cylindrical magnet

Name: Dhit sp. z o.o.
Address: Kościuszki 6A, Ożarów Mazowiecki, Poland, 05-850, PL
Telephone: +48 22 499 98 98
Price range: 1-6500
Rating: 5

cylindrical magnet

Catalog no 010475

GTIN: 5906301811138

5.00

Diameter Ø

8 mm [±0,1 mm]

Height

20 mm [±0,1 mm]

Weight

7.54 g

Magnetization Direction

→ diametrical

Load capacity

3.01 kg / 29.53 N

Magnetic Induction

607.01 mT

Coating

[NiCuNi] Nickel

4.60 ZŁ with VAT / pcs + price for transport

3.74 ZŁ net + 23% VAT / pcs

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MW 8x20 / N38 - cylindrical magnet

Specification / characteristics MW 8x20 / N38 - cylindrical magnet

properties

properties	values
Cat. no.	010475
GTIN	5906301811138
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	8 mm [±0,1 mm]
Height	20 mm [±0,1 mm]
Weight	7.54 g
Magnetization Direction	→ diametrical
Load capacity ~ ?	3.01 kg / 29.53 N
Magnetic Induction ~ ?	607.01 mT
Coating	[NiCuNi] Nickel
Manufacturing Tolerance	±0.1 mm

Magnetic properties of material N38

Specification / characteristics MW 8x20 / 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 magnet - report

Presented values are the outcome of a engineering calculation. Results are based on models for the class NdFeB. Actual parameters might slightly differ from theoretical values. Treat these data as a reference point for designers.

Table 1: Static pull force (pull vs gap) - characteristics
MW 8x20 / N38

Distance (mm)	Induction (Gauss) / mT	Pull Force (kg)	Risk Status
0 mm	6064 Gs 606.4 mT	3.01 kg / 3010.0 g 29.5 N	strong
1 mm	4587 Gs 458.7 mT	1.72 kg / 1722.0 g 16.9 N	weak grip
2 mm	3327 Gs 332.7 mT	0.91 kg / 906.1 g 8.9 N	weak grip
5 mm	1281 Gs 128.1 mT	0.13 kg / 134.3 g 1.3 N	weak grip
10 mm	389 Gs 38.9 mT	0.01 kg / 12.4 g 0.1 N	weak grip
15 mm	169 Gs 16.9 mT	0.00 kg / 2.3 g 0.0 N	weak grip
20 mm	90 Gs 9.0 mT	0.00 kg / 0.7 g 0.0 N	weak grip
30 mm	35 Gs 3.5 mT	0.00 kg / 0.1 g 0.0 N	weak grip
50 mm	10 Gs 1.0 mT	0.00 kg / 0.0 g 0.0 N	weak grip

Pulling power drops sharply per each millimeter of distance. Note that even a very thin break (e.g., contamination, varnish, dust) noticeably reduces the pull force. Neodymiums work strongest at the point of direct contact; air break kills the force. See how quickly the pull force plummet, when the magnet does not touch flatly to the steel surface. When designing the assembly, avoid redundant distances.

Table 2: Wall mounting (shearing) - vertical pull
MW 8x20 / N38

Surface type	Friction coefficient / % Mocy	Max load (kg)
Raw steel	µ = 0.3 30% Nominalnej Siły	0.90 kg / 903.0 g 8.9 N
Painted steel (standard)	µ = 0.2 20% Nominalnej Siły	0.60 kg / 602.0 g 5.9 N
Oily/slippery steel	µ = 0.1 10% Nominalnej Siły	0.30 kg / 301.0 g 3.0 N
Magnet with anti-slip rubber	µ = 0.5 50% Nominalnej Siły	1.51 kg / 1505.0 g 14.8 N

When placing a magnet on a upright plane (e.g., a board), it you can count on just approx. 1/5 of its nominal power. Gravity as well as a low friction coefficient mean that products move down easier than they pop off the substrate. Planning a hanger? Note that the shear force is much weaker than the maximum static pull force. On a slippery surface, the element will slide down under a noticeably lighter weight. Using a rubber pad can significantly raise the stability.

Table 3: Material efficiency (saturation) - power losses
MW 8x20 / N38

Steel thickness (mm)	% power	Real pull force (kg)
0.5 mm	10%	0.30 kg / 301.0 g 3.0 N
1 mm	25%	0.75 kg / 752.5 g 7.4 N
2 mm	50%	1.51 kg / 1505.0 g 14.8 N
5 mm	100%	3.01 kg / 3010.0 g 29.5 N
10 mm	100%	3.01 kg / 3010.0 g 29.5 N

A thin metal plate is unable to focus the entire magnetic field, which weakens actual performance of the holder. Should you attach a powerful product to a thin surface, the magnetism will penetrate right through and the holding will be smaller. To squeeze the maximum of this magnet's potential, you need a suitably thick element of metal. The saturation effect causes that on sheet metal structures (e.g., thin profiles), the holder works worse. We recommend selecting the steel thickness according to the table below.

Table 4: Thermal stability (stability) - resistance threshold
MW 8x20 / N38

Ambient temp. (°C)	Power loss	Remaining pull	Status
20 °C	0.0%	3.01 kg / 3010.0 g 29.5 N	OK
40 °C	-2.2%	2.94 kg / 2943.8 g 28.9 N	OK
60 °C	-4.4%	2.88 kg / 2877.6 g 28.2 N	OK
80 °C	-6.6%	2.81 kg / 2811.3 g 27.6 N
100 °C	-28.8%	2.14 kg / 2143.1 g 21.0 N

Classic neodymiums change their properties power after exceeding the maximum temperature. Protect against heat – high temperature can permanently damage this product. With increasing heat, the neodymium's power momentarily drops. Refrain from using this magnet near heat sources exceeding its safe range. Too high temperature will lead to destruction of magnetism.

Table 5: Magnet-Magnet interaction (attraction) - forces in the system
MW 8x20 / N38

Gap (mm)	Attraction (kg) (N-S)	Repulsion (kg) (N-N)
0 mm	4.52 kg / 4515.0 g 44.3 N	N/A
2 mm	1.37 kg / 1365.0 g 13.4 N	1.27 kg / 1274.0 g 12.5 N
5 mm	0.20 kg / 195.0 g 1.9 N	0.18 kg / 182.0 g 1.8 N
10 mm	0.02 kg / 15.0 g 0.1 N	0.01 kg / 14.0 g 0.1 N
20 mm	0.00 kg / 0.0 g 0.0 N	0.00 kg / 0.0 g 0.0 N
50 mm	0.00 kg / 0.0 g 0.0 N	0.00 kg / 0.0 g 0.0 N

Two magnets attract each other from a significantly greater distance than a magnet and sheet combination. The setup of two magnets generates a stronger field and a wider radius of operation. Want to build a powerful holder? Apply two magnets instead of one magnet and a steel. Remember that when attracting two neodymiums, the collision energy is huge. The levitation is a bit weaker than the connection force, but still significant.

Table 6: Protective zones (implants) - warnings
MW 8x20 / N38

Object / Device	Limit (Gauss) / mT	Safe distance
Pacemaker	5 Gs (0.5 mT)	6.5 cm
Hearing aid	10 Gs (1.0 mT)	5.0 cm
Timepiece	20 Gs (2.0 mT)	4.0 cm
Phone / Smartphone	40 Gs (4.0 mT)	3.0 cm
Remote	50 Gs (5.0 mT)	3.0 cm
Payment card	400 Gs (40.0 mT)	1.0 cm
HDD hard drive	600 Gs (60.0 mT)	1.0 cm

Extremely neodym field poses a serious hazard to electronics and medical implants. These NdFeB products produce a flux that prevents correct functioning of sensitive medical devices. Notice: the unseen radiation acts through matter and plastic. Special caution must be exercised by people with cochlear implants and insulin pumps. Influence will be felt by: automatic timepieces, remotes, speakers, and displays. Do not place the magnet near cards, HDD media, or sensitive navigation tools.

Table 7: Collisions (cracking risk) - warning
MW 8x20 / N38

Start from (mm)	Speed (km/h)	Energy (J)
10 mm	20.20 km/h (5.61 m/s)	0.12 J
30 mm	34.90 km/h (9.69 m/s)	0.35 J
50 mm	45.06 km/h (12.52 m/s)	0.59 J
100 mm	63.72 km/h (17.70 m/s)	1.18 J

Neodymium magnets are delicate – a strong collision with metal causes immediate chipping. Watch the impact speed – a neodymium left loose becomes dangerous. Striking energy can cause material chips or dangerous crushing to fingers. Hold the magnet firmly during mounting so it doesn't hit with great force against the metal. A collision at high speed almost guarantees destruction of the neodymium. Wear eye protection when handling with large magnets.

Table 8: Anti-corrosion coating durability
MW 8x20 / 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 9: Underwater work (magnet fishing)
MW 8x20 / N38

Environment	Effective steel pull	Effect
Air (land)	3.01 kg	Standard
Water (riverbed)	3.45 kg (+0.44 kg Buoyancy gain)	+14.5%

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

Water displaces steel, making heavy objects slightly lighter. However, remember the water resistance when pulling the rope quickly.

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MW 22x10 / N38 - cylindrical magnet

11.30 ZŁ brutto / pcs

The presented product is an exceptionally strong cylinder magnet, made from durable NdFeB material, which, with dimensions of Ø8x20 mm, guarantees the highest energy density. This specific item is characterized by high dimensional repeatability and industrial build quality, making it an ideal solution for professional engineers and designers. As a cylindrical magnet with significant force (approx. 3.01 kg), this product is in stock from our European logistics center, ensuring lightning-fast order fulfillment. Furthermore, its Ni-Cu-Ni coating effectively protects it against corrosion in standard operating conditions, ensuring an aesthetic appearance and durability for years.

This model is created for building electric motors, advanced Hall effect sensors, and efficient filters, where field concentration on a small surface counts. Thanks to the pull force of 29.53 N with a weight of only 7.54 g, this cylindrical magnet 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., 8.1 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 durability of the connection.

Grade N38 is the most frequently chosen standard for professional neodymium magnets, offering a great economic balance and operational stability. If you need the strongest magnets in the same volume (Ø8x20), 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 Ø8x20 mm, which, at a weight of 7.54 g, makes it an element with impressive magnetic energy density. The key parameter here is the lifting capacity amounting to approximately 3.01 kg (force ~29.53 N), which, with such defined dimensions, proves the high power of the NdFeB material. The product has a [NiCuNi] coating, which secures it against external factors, giving it an aesthetic, silvery shine.

Standardly, the magnetic axis runs through the center of the cylinder, causing the greatest attraction force to occur on the bases with a diameter of 8 mm. Such an arrangement is most desirable 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 diametrically if your project requires it.

Strengths as well as weaknesses of NdFeB magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
They maintain their magnetic properties even under close interference source,
In other words, due to the reflective layer of gold, the element becomes visually attractive,
Magnets have exceptionally strong magnetic induction on the surface,
Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
Thanks to versatility in forming and the ability to modify to unusual requirements,
Key role in modern technologies – they are used in magnetic memories, electric drive systems, medical devices, also technologically advanced constructions.
Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
Magnets exposed to a humid environment can rust. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
Limited ability of making threads in the magnet and complicated shapes - recommended is a housing - magnetic holder.
Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that small elements of these devices are able to complicate diagnosis medical when they are in the body.
With large orders the cost of neodymium magnets can be a barrier,

Highest magnetic holding force – what affects it?

Magnet power was defined for ideal contact conditions, assuming:

on a base made of structural steel, effectively closing the magnetic field
possessing a massiveness of min. 10 mm to ensure full flux closure
with a surface perfectly flat
without any air gap between the magnet and steel
during detachment in a direction perpendicular to the plane
at standard ambient temperature

Key elements affecting lifting force

In practice, the actual holding force is determined by a number of factors, ranked from crucial:

Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
Load vector – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
Steel thickness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped into the air.
Material type – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
Surface structure – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.

Safe handling of neodymium magnets

Permanent damage

Watch the temperature. Heating the magnet to high heat will ruin its properties and pulling force.

Crushing risk

Big blocks can break fingers in a fraction of a second. Never put your hand betwixt two strong magnets.

Impact on smartphones

GPS units and smartphones are highly susceptible to magnetic fields. Close proximity with a strong magnet can permanently damage the sensors in your phone.

Caution required

Use magnets with awareness. Their huge power can surprise even experienced users. Plan your moves and do not underestimate their power.

Keep away from children

NdFeB magnets are not intended for children. Swallowing multiple magnets can lead to them attracting across intestines, which poses a critical condition and necessitates immediate surgery.

Allergic reactions

A percentage of the population have a contact allergy to Ni, which is the typical protective layer for NdFeB magnets. Frequent touching might lead to skin redness. We suggest use protective gloves.

Magnets are brittle

Beware of splinters. Magnets can explode upon violent connection, ejecting shards into the air. Wear goggles.

Mechanical processing

Dust produced during grinding of magnets is combustible. Avoid drilling into magnets unless you are an expert.

Data carriers

Avoid bringing magnets close to a purse, laptop, or screen. The magnetic field can destroy these devices and erase data from cards.

Life threat

Warning for patients: Strong magnetic fields disrupt medical devices. Maintain minimum 30 cm distance or request help to work with the magnets.

Attention!

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

MW 8x20 / N38 - cylindrical magnet

MW 8x20 / N38 - cylindrical magnet

Magnetic properties of material N38

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical analysis of the magnet - report

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MW 45x35 / N38 - cylindrical magnet

MP 62x42x25 / N38 - ring magnet

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MW 22x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of NdFeB magnets.

Highest magnetic holding force – what affects it?

Key elements affecting lifting force

Safe handling of neodymium magnets

Physical properties of sintered neodymium magnets Nd₂Fe₁₄B at 20°C