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HH 20x7.2 [M4] / N38 - through hole magnetic holder

through hole magnetic holder

Catalog no 370481

GTIN/EAN: 5906301814917

5.00
Load capacity 8.00 kg / 78.45 N
Diameter Ø
20 mm [±1 mm]
Height
7.2 mm [±1 mm]
Weight
13.2 g
Magnetization Direction
↑ axial
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

technical specifications »

5.20 zł net / pcs

6.40 zł with VAT (23% VAT) / pcs

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Frequently asked questions

How much will a magnetic holder hold in practice?
The catalogue value assumes full contact with smooth steel at least 10 mm thick and a perpendicular pull. Thinner sheet, paint, rust and surface irregularities reduce it considerably: on 1 mm sheet about half remains. Lifting and vertical mounting call for an additional safety margin.
Will a holder work on stainless steel?
Not on austenitic grades 304 and 316 — they are effectively non-magnetic. It will not work on aluminium, copper or brass either. Those materials need a mechanical gripper.
Which coating for which conditions?
Nickel-copper-nickel (NiCuNi) is the standard and covers most applications. Epoxy is used for damp environments and outdoor work, zinc is sufficient for dry interiors. Holders in a steel housing or in rubber also protect the magnet against impact.

Guides from the knowledge base

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.

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Technical - HH 20x7.2 [M4] / N38 - through hole magnetic holder

Specification / characteristics - HH 20x7.2 [M4] / N38 - through hole magnetic holder

properties
properties values
Cat. no. 370481
GTIN/EAN 5906301814917
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 20 mm [±1 mm]
Height 7.2 mm [±1 mm]
Weight 13.2 g
Magnetization Direction ↑ axial
Load capacity ~ ? 8.00 kg / 78.45 N
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics HH 20x7.2 [M4] / N38 - through hole magnetic holder
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
Technical and environmental data

Material specification

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: 370481-2026
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Pulling force

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Unlike the countersunk version, the hole can be straight (for a cylindrical head screw) or with a recess (depending on the model). The steel housing strengthens attraction force and protects the magnet from cracking.
Similarly to other neodymium magnets, caution should be exercised when tightening the screw. Correct mounting guarantees long holder life without cracks.
Thanks to this, the through-hole holder has much greater lifting capacity than the magnet alone of these dimensions. This force is available with direct contact with metal.
These holders are ideal for mounting on non-magnetic surfaces such as wood, furniture board, plasterboard, or plastic. Great as mounting points in advertising and exhibition.
The product is intended mainly for use in dry rooms. This is not a stainless product (unless stated otherwise).

Advantages as well as disadvantages of rare earth magnets.

Advantages

Apart from their strong holding force, neodymium magnets have these key benefits:
  • They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
  • Neodymium magnets are highly resistant to demagnetization caused by magnetic disturbances,
  • The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to present itself better,
  • Magnets possess huge magnetic induction on the outer side,
  • Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
  • In view of the ability of free forming and adaptation to unique solutions, NdFeB magnets can be produced in a variety of forms and dimensions, which makes them more universal,
  • Huge importance in high-tech industry – they are commonly used in computer drives, brushless drives, 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 compact constructions

Limitations

Disadvantages of neodymium magnets:
  • At very strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
  • Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
  • When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
  • We suggest cover - magnetic mount, due to difficulties in creating threads inside the magnet and complex shapes.
  • Possible danger related to microscopic parts of magnets are risky, if swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these devices can complicate diagnosis medical in case of swallowing.
  • With mass production the cost of neodymium magnets is a challenge,

Lifting parameters

Maximum magnetic pulling force – what contributes to it?

The lifting capacity listed is a measurement result executed under specific, ideal conditions:
  • using a plate made of mild steel, functioning as a ideal flux conductor
  • with a cross-section of at least 10 mm
  • characterized by lack of roughness
  • with zero gap (no coatings)
  • under perpendicular force direction (90-degree angle)
  • at conditions approx. 20°C

Lifting capacity in real conditions – factors

Effective lifting capacity is influenced by working environment parameters, including (from priority):
  • Distance – the presence of foreign body (paint, tape, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
  • Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
  • Base massiveness – too thin plate does not close the flux, causing part of the power to be escaped to the other side.
  • Metal type – not every steel attracts identically. Alloy additives weaken the attraction effect.
  • Base smoothness – the more even the surface, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
  • Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the lifting capacity is smaller. Additionally, even a slight gap between the magnet’s surface and the plate decreases the lifting capacity.

Warnings
Physical harm

Mind your fingers. Two powerful magnets will join immediately with a force of massive weight, destroying everything in their path. Exercise extreme caution!

Protect data

Avoid bringing magnets near a wallet, laptop, or screen. The magnetism can destroy these devices and erase data from cards.

Safe operation

Before use, check safety instructions. Sudden snapping can break the magnet or injure your hand. Be predictive.

Product not for children

Neodymium magnets are not suitable for play. Swallowing a few magnets can lead to them connecting inside the digestive tract, which poses a critical condition and requires urgent medical intervention.

Mechanical processing

Machining of NdFeB material carries a risk of fire hazard. Magnetic powder oxidizes rapidly with oxygen and is hard to extinguish.

Compass and GPS

Be aware: neodymium magnets generate a field that confuses sensitive sensors. Keep a separation from your mobile, device, and navigation systems.

Danger to pacemakers

For implant holders: Powerful magnets disrupt electronics. Keep at least 30 cm distance or ask another person to work with the magnets.

Sensitization to coating

Medical facts indicate that the nickel plating (the usual finish) is a strong allergen. For allergy sufferers, refrain from direct skin contact or choose versions in plastic housing.

Demagnetization risk

Watch the temperature. Exposing the magnet to high heat will ruin its magnetic structure and pulling force.

Material brittleness

Watch out for shards. Magnets can explode upon uncontrolled impact, launching sharp fragments into the air. Wear goggles.

Danger! Need more info? Check our post: Are neodymium magnets dangerous?