← previous
next →
Product available Ships today (order by 14:00) CO2 GPSR PPWR REACH

MPL 42x20x5 / N38 - lamellar magnet

lamellar magnet

Catalog no 020163

GTIN/EAN: 5906301811695

5.00
Load capacity 11.06 kg / 108.46 N Magnetic Induction 203.37 mT / 2034 Gs
length
42 mm [±0,1 mm]
Width
20 mm [±0,1 mm]
Height
5 mm [±0,1 mm]
Weight
31.5 g
Magnetization Direction
↑ axial
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

see specifications »

12.70 zł net / pcs

15.62 zł with VAT (23% VAT) / pcs

price for transport

bulk discounts:

Need more?
Quantity
Net
Gross
price from 1 pcs
12.70 zł
15.62 zł
price from 50 pcs
11.94 zł
14.68 zł
price from 200 pcs
11.18 zł
13.75 zł

Frequently asked questions

How much will a block magnet really hold?
The catalogue force is measured in full contact with smooth steel at least 10 mm thick, pulled perpendicular, at about 20 °C. On 1 mm sheet about 50% of that value remains, on 0.5 mm about 25%. Mounted on a vertical wall the realistic figure is 20–30%, because the load is then in shear rather than in tension.
What is the maximum working temperature?
Standard N-series grades up to 80 °C, and N50, N52 and N54 up to 60 °C. Above the maximum working temperature the loss stops being reversible. The Curie temperature, at which magnetic properties are lost completely, is about 310 °C.
What safety factor should I allow?
At least twice the mass of the item, and three to five times for vertical mounting. The margin covers sheet thickness, surface condition, any layer of paint or rust, and vibration.

Guides from the knowledge base

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.

PDF report Calculator
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 data - MPL 42x20x5 / N38 - lamellar magnet

Specification / characteristics - MPL 42x20x5 / N38 - lamellar magnet

properties
properties values
Cat. no. 020163
GTIN/EAN 5906301811695
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
length 42 mm [±0,1 mm]
Width 20 mm [±0,1 mm]
Height 5 mm [±0,1 mm]
Weight 31.5 g
Magnetization Direction ↑ axial
Load capacity ~ ? 11.06 kg / 108.46 N
Magnetic Induction ~ ? 203.37 mT / 2034 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MPL 42x20x5 / N38 - lamellar 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 analysis of the magnet - data

The following data represent the result of a engineering calculation. Results were calculated on models for the material Nd2Fe14B. Real-world parameters might slightly deviate from the simulation results. Use these data as a preliminary roadmap for designers.

Table 1: Static pull force (force vs gap) - interaction chart
MPL 42x20x5 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 2033 Gs
203.3 mT
 11.06 kg / 24.38 pounds
11060.0 g / 108.5 N
 critical level
1 mm 1938 Gs
193.8 mT
 10.05 kg / 22.15 pounds
10049.3 g / 98.6 N
 critical level
2 mm 1823 Gs
182.3 mT
 8.89 kg / 19.60 pounds
8888.2 g / 87.2 N
 strong
3 mm 1696 Gs
169.6 mT
 7.69 kg / 16.96 pounds
7691.7 g / 75.5 N
 strong
5 mm 1433 Gs
143.3 mT
 5.49 kg / 12.10 pounds
5490.3 g / 53.9 N
 strong
10 mm 885 Gs
88.5 mT
 2.09 kg / 4.62 pounds
2093.5 g / 20.5 N
 strong
15 mm 547 Gs
54.7 mT
 0.80 kg / 1.76 pounds
799.6 g / 7.8 N
 weak grip
20 mm 350 Gs
35.0 mT
 0.33 kg / 0.72 pounds
327.0 g / 3.2 N
 weak grip
30 mm 160 Gs
16.0 mT
 0.07 kg / 0.15 pounds
68.5 g / 0.7 N
 weak grip
50 mm 48 Gs
4.8 mT
 0.01 kg / 0.01 pounds
6.2 g / 0.1 N
 weak grip
Magnetic force weakens drastically with every subsequent millimeter of gap. Keep in mind that even a microscopic distance (e.g., dirt, paint, rust) strongly reduces the pull force. Magnetic products operate most effectively in perfect adhesion; distance drastically cuts the power. Notice how quickly the parameters drop, when the product does not touch flatly to the steel surface. When calculating the arrangement, discard additional spacers.

Table 2: Slippage capacity (vertical surface)
MPL 42x20x5 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 2.21 kg / 4.88 pounds
2212.0 g / 21.7 N
1 mm Stal (~0.2) 2.01 kg / 4.43 pounds
2010.0 g / 19.7 N
2 mm Stal (~0.2) 1.78 kg / 3.92 pounds
1778.0 g / 17.4 N
3 mm Stal (~0.2) 1.54 kg / 3.39 pounds
1538.0 g / 15.1 N
5 mm Stal (~0.2) 1.10 kg / 2.42 pounds
1098.0 g / 10.8 N
10 mm Stal (~0.2) 0.42 kg / 0.92 pounds
418.0 g / 4.1 N
15 mm Stal (~0.2) 0.16 kg / 0.35 pounds
160.0 g / 1.6 N
20 mm Stal (~0.2) 0.07 kg / 0.15 pounds
66.0 g / 0.6 N
30 mm Stal (~0.2) 0.01 kg / 0.03 pounds
14.0 g / 0.1 N
50 mm Stal (~0.2) 0.00 kg / 0.00 pounds
2.0 g / 0.0 N
The following data shows the theoretical shear load sufficient to cause the downward movement of the magnet downwards on a vertical steel wall (assuming typical friction coefficient). The holding force is relative to the gap size between the magnet and the surface.

Table 3: Wall mounting (shearing) - behavior on slippery surfaces
MPL 42x20x5 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
3.32 kg / 7.31 pounds
3318.0 g / 32.5 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
2.21 kg / 4.88 pounds
2212.0 g / 21.7 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
1.11 kg / 2.44 pounds
1106.0 g / 10.8 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
5.53 kg / 12.19 pounds
5530.0 g / 54.2 N
When mounting a element on a vertical surface (e.g., a board), it you can count on just about 20%-30% of nominal attraction strength. Gravitational force as well as a low friction coefficient mean that magnets slip faster than they pull off. Planning a wall mount? Remember that the shear force is noticeably lower than the maximum static pull force. On a smooth steel, the element will give way down under a noticeably lighter weight. Utilizing a rubberized layer can significantly raise the stability.

Table 4: Material efficiency (substrate influence) - sheet metal selection
MPL 42x20x5 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
5%
 0.55 kg / 1.22 pounds
553.0 g / 5.4 N
1 mm
13%
 1.38 kg / 3.05 pounds
1382.5 g / 13.6 N
2 mm
25%
 2.77 kg / 6.10 pounds
2765.0 g / 27.1 N
3 mm
38%
 4.15 kg / 9.14 pounds
4147.5 g / 40.7 N
5 mm
63%
 6.91 kg / 15.24 pounds
6912.5 g / 67.8 N
10 mm
100%
 11.06 kg / 24.38 pounds
11060.0 g / 108.5 N
11 mm
100%
 11.06 kg / 24.38 pounds
11060.0 g / 108.5 N
12 mm
100%
 11.06 kg / 24.38 pounds
11060.0 g / 108.5 N
A too thin steel is unable to focus the entire magnetic field, which weakens actual performance of the holder. If you install a neodymium to a thin surface, the field will penetrate right through and the pull force will drop sharply. To utilize the maximum of this magnet's power, you require a sufficiently solid piece of metal. The material oversaturation causes that on delicate walls (e.g., car bodies), the product works worse. We suggest choosing the steel thickness from these parameters.

Table 5: Thermal resistance (stability) - power drop
MPL 42x20x5 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 11.06 kg / 24.38 pounds
11060.0 g / 108.5 N
 OK
40 °C -2.2% 10.82 kg / 23.85 pounds
10816.7 g / 106.1 N
 OK
60 °C -4.4% 10.57 kg / 23.31 pounds
10573.4 g / 103.7 N
80 °C -6.6% 10.33 kg / 22.77 pounds
10330.0 g / 101.3 N
100 °C -28.8% 7.87 kg / 17.36 pounds
7874.7 g / 77.3 N
Ordinary NdFeB products change their properties strength after exceeding the maximum temperature. Avoid high temperatures – excessive heat can irreversibly demagnetize this product. With increasing heat, the magnet's capacity momentarily decreases. Avoid using this product in hot environments higher than its safe range. Exceeding the critical threshold will cause irreversible degradation of magnetism.
*Important note: Thermal stability is determined by both grade, and the Permeance Coefficient Pc. Low-profile magnets (pancake types) are more susceptible to demagnetization sooner than taller cylinders. Red status in the table points to a risk of irreversible loss for this specific geometry.

Table 6: Two magnets (repulsion) - field collision
MPL 42x20x5 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Shear Force (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 21.41 kg / 47.21 pounds
3 465 Gs
3.21 kg / 7.08 pounds
3212 g / 31.5 N
 N/A
1 mm 20.49 kg / 45.17 pounds
3 978 Gs
3.07 kg / 6.78 pounds
3074 g / 30.2 N
 18.44 kg / 40.66 pounds
~0 Gs
2 mm 19.46 kg / 42.89 pounds
3 877 Gs
2.92 kg / 6.43 pounds
2918 g / 28.6 N
 17.51 kg / 38.60 pounds
~0 Gs
3 mm 18.35 kg / 40.46 pounds
3 765 Gs
2.75 kg / 6.07 pounds
2753 g / 27.0 N
 16.52 kg / 36.41 pounds
~0 Gs
5 mm 16.05 kg / 35.38 pounds
3 521 Gs
2.41 kg / 5.31 pounds
2407 g / 23.6 N
 14.44 kg / 31.84 pounds
~0 Gs
10 mm 10.63 kg / 23.43 pounds
2 865 Gs
1.59 kg / 3.52 pounds
1594 g / 15.6 N
 9.57 kg / 21.09 pounds
~0 Gs
20 mm 4.05 kg / 8.94 pounds
1 769 Gs
0.61 kg / 1.34 pounds
608 g / 6.0 N
 3.65 kg / 8.04 pounds
~0 Gs
50 mm 0.28 kg / 0.62 pounds
465 Gs
0.04 kg / 0.09 pounds
42 g / 0.4 N
 0.25 kg / 0.55 pounds
~0 Gs
60 mm 0.13 kg / 0.29 pounds
320 Gs
0.02 kg / 0.04 pounds
20 g / 0.2 N
 0.12 kg / 0.26 pounds
~0 Gs
70 mm 0.07 kg / 0.15 pounds
228 Gs
0.01 kg / 0.02 pounds
10 g / 0.1 N
 0.06 kg / 0.13 pounds
~0 Gs
80 mm 0.04 kg / 0.08 pounds
167 Gs
0.01 kg / 0.01 pounds
5 g / 0.1 N
 0.03 kg / 0.07 pounds
~0 Gs
90 mm 0.02 kg / 0.04 pounds
125 Gs
0.00 kg / 0.01 pounds
3 g / 0.0 N
 0.02 kg / 0.04 pounds
~0 Gs
100 mm 0.01 kg / 0.03 pounds
96 Gs
0.00 kg / 0.00 pounds
2 g / 0.0 N
 0.01 kg / 0.02 pounds
~0 Gs
Two magnets attract each other from a much further distance than a magnet and sheet setup. The setup of two magnets produces a massive flux and a larger range of action. Want to build a powerful holder? Apply two magnets instead of a neodymium and a steel. Exercise caution that when attracting two neodymiums, the pinch force is extreme. The repulsion force is a bit weaker than the attraction, but still significant.
*The magnetic induction in repulsion mode is approximately ~0 Gs at the geometric center of the gap (resulting from vector opposition).
* Figures demonstrate sliding force of dual identical magnets (friction coefficient ~0.15 for Ni-Ni plating).

Table 7: Hazards (implants) - warnings
MPL 42x20x5 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 11.5 cm
Hearing aid 10 Gs (1.0 mT) 9.0 cm
Mechanical watch 20 Gs (2.0 mT) 7.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 5.5 cm
Remote 50 Gs (5.0 mT) 5.0 cm
Payment card 400 Gs (40.0 mT) 2.0 cm
HDD hard drive 600 Gs (60.0 mT) 1.5 cm
Extremely neodym field poses a real danger to electronic devices as well as medical implants. These neodymiums produce a flux that prevents correct functioning of digital equipment. Notice: the invisible magnetic field acts through matter and housings. Exceptional care must be exercised by people with cochlear implants and drug dispensers. Influence will be felt by: mechanical watches, remotes, membranes, and displays. Do not place the magnet near cards, hard drives, or sensitive navigation tools.

Table 8: Collisions (cracking risk) - warning
MPL 42x20x5 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 21.88 km/h
(6.08 m/s)
 0.58 J
30 mm 23.81 km/h
(6.61 m/s)
 0.69 J
50 mm 23.88 km/h
(6.63 m/s)
 0.69 J
100 mm 23.91 km/h
(6.64 m/s)
 0.69 J
NdFeB products are delicate – a strong collision with metal risks their cracking. Watch the impact speed – a magnet released freely speeds with massive force. Kinetic force can destroy the magnet or injury to fingers. Be sure to control the product during mounting so it doesn't slam with momentum against the metal. A collision at high speed means shattering of the neodymium. Use safety goggles when working with powerful specimens.

Table 9: Surface protection spec
MPL 42x20x5 / 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)
For outdoor applications, an epoxy coating is required; standard nickel is intended for indoor use. Improper coating selection is the most common cause of magnet failure over time.

Table 10: Construction data (Flux)
MPL 42x20x5 / N38

Parameter Value SI Unit / Description
Magnetic Flux 18 614 Mx 186.1 µWb
Pc Coefficient 0.23 Low (Flat)
Total magnetic flux passing through the magnet pole. Essential parameter when building generators and motors. Pc value defines the magnet's operating point.

Table 11: Submerged application
MPL 42x20x5 / N38

Environment Effective steel pull Effect
Air (land) 11.06 kg Standard
Water (riverbed) 12.66 kg
(+1.60 kg buoyancy gain)
+14.5%
Corrosion warning: Standard nickel requires drying after every contact with moisture; lack of maintenance will lead to rust spots.
The magnetic field penetrates through water without any losses. As a result, your magnet will pull a heavier object from the bottom than if you lifted it in the air.

1. Wall mount (shear)

*Warning: On a vertical wall, the magnet holds merely ~20% of its perpendicular strength.

2. Steel saturation

*Thin metal sheet (e.g. computer case) severely weakens the holding force.

3. Heat tolerance

*For standard magnets, the safety limit is 80°C.

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

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 0.23

The chart above illustrates the magnetic characteristics of the material within the second quadrant of the hysteresis loop. 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 specification and ecology

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%

Ecology and recycling (GPSR)

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: 020163-2026
Measurement Calculator

Pulling force

Field Strength

Enter a value into a field, to see the rest convert automatically.

Other proposals

MPL 25x25x10 / N38 - lamellar magnet
Product available Ships today (order by 14:00)

MPL 25x25x10 / N38 - lamellar magnet

20.29 zł brutto / pcs
MW 20x1.5 / N38 - cylindrical magnet
Product available Ships today (order by 14:00)

MW 20x1.5 / N38 - cylindrical magnet

1.574 zł brutto / pcs
MPL 35x35x10 / N38 - lamellar magnet
Product available Ships today (order by 14:00)

MPL 35x35x10 / N38 - lamellar magnet

35.10 zł brutto / pcs
MP 30x7/3x3 / N38 - ring magnet
Product available Ships today (order by 14:00)

MP 30x7/3x3 / N38 - ring magnet

6.84 zł brutto / pcs
This product is a very powerful magnet in the shape of a plate made of NdFeB material, which, with dimensions of 42x20x5 mm and a weight of 31.5 g, guarantees premium class connection. As a magnetic bar with high power (approx. 11.06 kg), this product is available immediately from our warehouse in Poland. Additionally, its Ni-Cu-Ni coating secures it against corrosion in standard operating conditions, giving it an aesthetic appearance.
Separating block magnets requires a technique based on sliding (moving one relative to the other), rather than forceful pulling apart. To separate the MPL 42x20x5 / N38 model, firmly slide one magnet over the edge of the other until the attraction force decreases. We recommend extreme caution, because after separation, the magnets may want to violently snap back together, which threatens pinching the skin. Never use metal tools for prying, as the brittle NdFeB material may chip and damage your eyes.
Plate magnets MPL 42x20x5 / N38 are the foundation for many industrial devices, such as magnetic separators and linear motors. They work great as fasteners under tiles, wood, or glass. Their rectangular shape facilitates precise gluing into milled sockets in wood or plastic.
Cyanoacrylate glues (super glue type) are good only for small magnets; for larger plates, we recommend resins. For lighter applications or mounting on smooth surfaces, branded foam tape (e.g., 3M VHB) will work, provided the surface is perfectly degreased. Remember to clean and degrease the magnet surface before gluing, which significantly increases the adhesion of the glue to the nickel coating.
Standardly, the MPL 42x20x5 / N38 model is magnetized axially (dimension 5 mm), which means that the N and S poles are located on its largest, flat surfaces. Thanks to this, it works best when "sticking" to sheet metal or another magnet with a large surface area. Such a pole arrangement ensures maximum holding capacity when pressing against the sheet, creating a closed magnetic circuit.
The presented product is a neodymium magnet with precisely defined parameters: 42 mm (length), 20 mm (width), and 5 mm (thickness). It is a magnetic block with dimensions 42x20x5 mm and a self-weight of 31.5 g, ready to work at temperatures up to 80°C. The protective [NiCuNi] coating secures the magnet against corrosion.

Strengths as well as weaknesses of Nd2Fe14B magnets.

Pros

Besides their tremendous field intensity, neodymium magnets offer the following advantages:
  • Their power is durable, and after around 10 years it decreases only by ~1% (theoretically),
  • They are extremely resistant to demagnetization induced by external field influence,
  • In other words, due to the shiny finish of silver, the element becomes visually attractive,
  • Neodymium magnets achieve maximum magnetic induction on a their surface, which allows for strong attraction,
  • Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
  • Due to the potential of flexible molding and adaptation to custom requirements, neodymium magnets can be created in a variety of forms and dimensions, which amplifies use scope,
  • Universal use in advanced technology sectors – they serve a role in mass storage devices, electric drive systems, medical devices, as well as complex engineering applications.
  • Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages

Drawbacks and weaknesses of neodymium magnets: application proposals
  • They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
  • Neodymium magnets decrease their strength 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
  • Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
  • Limited ability of creating threads in the magnet and complicated shapes - recommended is cover - mounting mechanism.
  • Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child safety. Additionally, tiny parts of these magnets are able to be problematic in diagnostics medical when they are in the body.
  • With large orders the cost of neodymium magnets can be a barrier,

Lifting parameters

Detachment force of the magnet in optimal conditions – what it depends on?

The load parameter shown refers to the maximum value, recorded under laboratory conditions, namely:
  • on a base made of structural steel, perfectly concentrating the magnetic field
  • whose transverse dimension reaches at least 10 mm
  • characterized by even structure
  • without the slightest clearance between the magnet and steel
  • for force acting at a right angle (in the magnet axis)
  • in temp. approx. 20°C

Key elements affecting lifting force

Bear in mind that the working load may be lower influenced by elements below, starting with the most relevant:
  • Distance (between the magnet and the metal), because even a very small clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to paint, rust or debris).
  • Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
  • Base massiveness – too thin steel causes magnetic saturation, causing part of the flux to be escaped into the air.
  • Material type – the best choice is high-permeability steel. Cast iron may attract less.
  • Smoothness – ideal contact is obtained only on polished steel. Any scratches and bumps create air cushions, reducing force.
  • Heat – neodymium magnets have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a small distance between the magnet and the plate lowers the load capacity.

Safety rules for work with NdFeB magnets
Electronic hazard

Data protection: Neodymium magnets can damage data carriers and delicate electronics (pacemakers, medical aids, mechanical watches).

Physical harm

Big blocks can break fingers in a fraction of a second. Under no circumstances place your hand betwixt two attracting surfaces.

Safe operation

Handle with care. Neodymium magnets attract from a distance and snap with huge force, often faster than you can react.

Metal Allergy

Some people experience a contact allergy to Ni, which is the typical protective layer for NdFeB magnets. Prolonged contact can result in an allergic reaction. We recommend use protective gloves.

Do not drill into magnets

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

Implant safety

Patients with a heart stimulator should keep an safe separation from magnets. The magnetic field can disrupt the functioning of the life-saving device.

GPS and phone interference

A powerful magnetic field disrupts the functioning of compasses in phones and navigation systems. Maintain magnets close to a smartphone to avoid damaging the sensors.

Permanent damage

Regular neodymium magnets (N-type) lose magnetization when the temperature exceeds 80°C. Damage is permanent.

Risk of cracking

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

Swallowing risk

These products are not toys. Accidental ingestion of multiple magnets can lead to them attracting across intestines, which poses a critical condition and requires immediate surgery.

Caution! More info about hazards in the article: Safety of working with magnets.