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UMGGW 66x8.5 [M8] GW / N38 - magnetic holder rubber internal thread

magnetic holder rubber internal thread

Catalog no 160308

GTIN/EAN: 5906301813668

5.00
Load capacity 18.40 kg / 180.44 N
Diameter Ø
66 mm [±1 mm]
Height
8.5 mm [±1 mm]
Weight
100 g

How we measure these parameters — certificates and measurements

see parameters »

19.00 zł net / pcs

23.37 zł with VAT (23% VAT) / pcs

price for transport

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23.37 zł
price from 20 pcs
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21.97 zł
price from 50 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 - UMGGW 66x8.5 [M8] GW / N38 - magnetic holder rubber internal thread

Specification / characteristics - UMGGW 66x8.5 [M8] GW / N38 - magnetic holder rubber internal thread

properties
properties values
Cat. no. 160308
GTIN/EAN 5906301813668
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 66 mm [±1 mm]
Height 8.5 mm [±1 mm]
Weight 100 g
Load capacity ~ ? 18.40 kg / 180.44 N
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics UMGGW 66x8.5 [M8] GW / N38 - magnetic holder rubber internal thread
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 specification and ecology

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%

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: 160308-2026
Measurement Calculator

Magnet pull force

Magnetic Induction

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Magnets in rubber were created for non-invasive mounting on sensitive painted surfaces, such as car bodies or machine casings. Used for mounting taxi beacons, antennas, cameras, and license plates at rallies, where mobility counts. The internal threaded bushing allows quick mounting of any element, creating a solid mounting point without drilling holes in the sheet metal.
Yes, thanks to the hermetic rubber coating, these magnets are fully waterproof and protected against corrosion. Santoprene rubber does not rot in the sun and retains flexibility even during frosts, guaranteeing long life. This is the best choice for mounting on a car roof, because you can be sure that rusty stains will not appear on the paint after rain.
Rubber has a very high coefficient of friction, which makes the holder extremely difficult to move sideways (high shear force acts). Thanks to this, these magnets hold onto the car roof excellently even at high speeds and wind resistance. They ensure maximum stability of mounting under vibrations, which is crucial in transport and automotive.
You can screw any metric bolt, hook, handle, cable holder into the magnet or screw the device housing directly. Just remember to choose the appropriate screw length – too long can push the rubber from the bottom and damage the paint.
Inside there are several magnets arranged with alternating poles on a steel plate, which closes the magnetic field close to the surface. This is much safer for electronics inside the vehicle (e.g., under the roof) compared to regular magnets.

Advantages and disadvantages of rare earth magnets.

Strengths

Apart from their superior magnetic energy, neodymium magnets have these key benefits:
  • They do not lose strength, even after around ten years – the reduction in power is only ~1% (theoretically),
  • They are noted for resistance to demagnetization induced by presence of other magnetic fields,
  • The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
  • The surface of neodymium magnets generates a intense magnetic field – this is one of their assets,
  • 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...
  • Possibility of accurate machining and adapting to concrete needs,
  • Fundamental importance in modern technologies – they find application in HDD drives, electromotive mechanisms, medical devices, and industrial machines.
  • Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages

Drawbacks and weaknesses of neodymium magnets and proposals for their use:
  • To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
  • 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 suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
  • Limited ability of creating threads in the magnet and complicated shapes - preferred is a housing - mounting mechanism.
  • Health risk related to microscopic parts of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these magnets are able to disrupt the diagnostic process medical when they are in the body.
  • Due to complex production process, their price is relatively high,

Holding force characteristics

Best holding force of the magnet in ideal parameters – what it depends on?

Holding force of 18.40 kg is a result of laboratory testing executed under the following configuration:
  • using a sheet made of high-permeability steel, serving as a ideal flux conductor
  • possessing a thickness of min. 10 mm to avoid saturation
  • with a plane free of scratches
  • without the slightest air gap between the magnet and steel
  • for force acting at a right angle (pull-off, not shear)
  • at conditions approx. 20°C

Practical aspects of lifting capacity – factors

During everyday use, the actual lifting capacity depends on several key aspects, listed from most significant:
  • Distance – the presence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
  • Direction of force – maximum parameter is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
  • Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the flux to be escaped into the air.
  • Material composition – different alloys reacts the same. Alloy additives worsen the attraction effect.
  • Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
  • Thermal environment – heating the magnet causes a temporary drop of induction. Check the maximum operating temperature for a given model.

Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance between the magnet’s surface and the plate reduces the holding force.

Warnings
Electronic hazard

Equipment safety: Neodymium magnets can damage payment cards and sensitive devices (heart implants, hearing aids, mechanical watches).

Medical implants

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

Impact on smartphones

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

Permanent damage

Monitor thermal conditions. Exposing the magnet above 80 degrees Celsius will permanently weaken its magnetic structure and pulling force.

Material brittleness

Neodymium magnets are ceramic materials, meaning they are fragile like glass. Collision of two magnets leads to them shattering into small pieces.

Adults only

Adult use only. Tiny parts can be swallowed, leading to intestinal necrosis. Store away from kids and pets.

Machining danger

Powder created during grinding of magnets is self-igniting. Do not drill into magnets without proper cooling and knowledge.

Crushing force

Large magnets can smash fingers in a fraction of a second. Do not put your hand betwixt two strong magnets.

Nickel coating and allergies

Studies show that nickel (the usual finish) is a potent allergen. For allergy sufferers, refrain from touching magnets with bare hands or choose encased magnets.

Conscious usage

Use magnets consciously. Their huge power can shock even professionals. Stay alert and do not underestimate their power.

Warning! Learn more about hazards in the article: Safety of working with magnets.