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UMT 12x20 black / N38 - board holder

board holder

Catalog no 230285

GTIN/EAN: 5906301814375

5.00
Diameter Ø
12 mm [±1 mm]
Height
20 mm [±1 mm]
Weight
3.5 g
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

see properties »

1.540 zł net / pcs

1.894 zł with VAT (23% VAT) / pcs

price for transport

bulk discounts:

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price from 250 pcs
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Frequently asked questions

How many sheets of paper will one magnetic pin hold?
The category description quotes <strong>up to 20 sheets of A4</strong>, and that is the number to start from. It is not fixed: a magnet holds more firmly on a thicker base — a fridge door or a solid whiteboard backing gives more than the thin sheet behind a cheap dry-wipe board. Paper matters too: twenty sheets of office weight is not the same as twenty sheets of coated stock. For thicker stacks and folders take a larger size, 20x25 or 29x38 mm — a bigger contact area than 12x20.
Will a magnetic pin stick to any board - whiteboard, glass, cork?
No, not to every surface — a magnet only holds on a ferromagnetic material, which usually means whiteboards and glass boards that have a steel sheet underneath. Plain glass without a metal backing won't attract the magnet at all. Cork boards mostly lack a metal layer too, so the pin won't stick unless the manufacturer specifically states the board is magnetic. Before buying, a simple test helps — try any magnet against the board in the shop or at home.
Will the magnet leave a mark or scratch the board or the fridge?
No, under normal use the pin leaves no lasting mark or scratch — the bottom of the magnet has an ergonomic, smooth shape designed for contact with smooth surfaces like a lacquered fridge door or a laminated board. The risk appears only when sliding the magnet across a surface with trapped grit or other hard particles caught between the base and the board — that can cause a light scratch, the same as with any object dragged across a painted surface. Wiping the magnet's base regularly removes this risk.
What is the difference between the 12x20 and 20x25 sizes, and which one suits an office?
The main difference is holding strength and grip comfort — the UMT 20x25 has a larger magnet surface, so it holds a thicker stack of sheets more firmly and is easier to grab with your fingers. The UMT 12x20 is compact and works better where board space is tight, for example with many small notes side by side. For a typical office board holding a few sheets and schedules, both sizes work fine — the choice mainly comes down to whether holding strength or fitting more pins side by side matters more.
Are magnetic pins suitable for large-format maps and plans?
Yes, they work well for that — the larger UMT 20x25 variant is well suited to maps and plans hung on magnetic boards in offices, on construction sites, or in planning rooms, since it holds heavier, stiffer paper better than the smaller pin. For a large format, it helps to place several pins along the corners and edges of the plan rather than just one in the center — this spreads the pressure and prevents the paper from sagging under its own weight.

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 - UMT 12x20 black / N38 - board holder

Specification / characteristics - UMT 12x20 black / N38 - board holder

properties
properties values
Cat. no. 230285
GTIN/EAN 5906301814375
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 12 mm [±1 mm]
Height 20 mm [±1 mm]
Weight 3.5 g
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics UMT 12x20 black / N38 - board 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
Engineering data and GPSR

Chemical composition

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%

Environmental data

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: 230285-2026
Measurement Calculator

Pulling force

Magnetic Induction

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This shape makes operating a whiteboard convenient, fast, and does not break nails. Small size hides great power - one pin works better than a handful of regular magnets. It's a professional choice for office, school, conference room, and home.
The force of these magnets allows pinning a thick file of documents, photos, posters, or drawings. They are many times stronger than traditional black ferrite magnets found in markets.
They work well as markers on maps, scoreboards, planners, or Kanban systems. They are safe to use thanks to the plastic housing, which has no sharp edges. Check the description if this model is dedicated to glass boards (weak magnets do not work through glass).
Due to small size, pins are not suitable for small children under 3 years old. For older children, they are a great scientific aid for physics experiments.
We offer a wide color range: red, blue, green, yellow, white, black, and many others. Check purchasing options (pieces or blisters) in the product details above.

Strengths as well as weaknesses of neodymium magnets.

Pros

In addition to their pulling strength, neodymium magnets provide the following advantages:
  • They have stable power, and over nearly 10 years their attraction force decreases symbolically – ~1% (in testing),
  • They show high resistance to demagnetization induced by external magnetic fields,
  • The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to present itself better,
  • They show high magnetic induction at the operating surface, which affects their effectiveness,
  • Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
  • Possibility of precise machining and adapting to defined conditions,
  • Universal use in modern technologies – they are commonly used in HDD drives, motor assemblies, diagnostic systems, also other advanced devices.
  • Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages

Drawbacks and weaknesses of neodymium magnets and ways of using them
  • They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
  • When exposed to high temperature, neodymium magnets experience a drop in force. 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
  • Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
  • Due to limitations in realizing nuts and complex forms in magnets, we propose using cover - magnetic mechanism.
  • Potential hazard related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that tiny parts of these devices are able to disrupt the diagnostic process medical when they are in the body.
  • With budget limitations the cost of neodymium magnets can be a barrier,

Lifting parameters

Maximum lifting force for a neodymium magnet – what it depends on?

The declared magnet strength refers to the peak performance, recorded under optimal environment, namely:
  • with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
  • whose transverse dimension is min. 10 mm
  • characterized by smoothness
  • with total lack of distance (without impurities)
  • under axial application of breakaway force (90-degree angle)
  • at temperature room level

Practical aspects of lifting capacity – factors

It is worth knowing that the magnet holding may be lower subject to elements below, starting with the most relevant:
  • Space between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
  • Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
  • Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
  • Material type – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
  • Plate texture – smooth surfaces guarantee perfect abutment, which improves field saturation. Uneven metal reduce efficiency.
  • Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a minimal clearance between the magnet’s surface and the plate decreases the holding force.

Warnings
Magnet fragility

Despite metallic appearance, neodymium is delicate and cannot withstand shocks. Do not hit, as the magnet may shatter into hazardous fragments.

Do not underestimate power

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

Safe distance

Do not bring magnets close to a purse, computer, or TV. The magnetism can destroy these devices and wipe information from cards.

Hand protection

Pinching hazard: The pulling power is so great that it can cause blood blisters, crushing, and even bone fractures. Protective gloves are recommended.

Dust is flammable

Machining of NdFeB material carries a risk of fire risk. Magnetic powder reacts violently with oxygen and is difficult to extinguish.

Permanent damage

Standard neodymium magnets (N-type) lose magnetization when the temperature surpasses 80°C. The loss of strength is permanent.

Precision electronics

Navigation devices and mobile phones are highly sensitive to magnetic fields. Direct contact with a strong magnet can permanently damage the sensors in your phone.

Pacemakers

Warning for patients: Powerful magnets disrupt electronics. Keep minimum 30 cm distance or ask another person to handle the magnets.

Nickel coating and allergies

It is widely known that the nickel plating (the usual finish) is a common allergen. For allergy sufferers, prevent direct skin contact and select coated magnets.

Adults only

Absolutely store magnets out of reach of children. Choking hazard is significant, and the consequences of magnets clamping inside the body are very dangerous.

Important! Details about risks in the article: Magnet Safety Guide.