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UMGGW 29x8 [M4] GW / N38 - magnetic holder rubber internal thread

magnetic holder rubber internal thread

Catalog no 160305

GTIN/EAN: 5906301813637

5.00
Load capacity 6.40 kg / 62.76 N
Diameter Ø
29 mm [±1 mm]
Height
8 mm [±1 mm]
Weight
18 g

How we measure these parameters — certificates and measurements

technical parameters »

7.00 zł net / pcs

8.61 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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Product card - UMGGW 29x8 [M4] GW / N38 - magnetic holder rubber internal thread

Specification / characteristics - UMGGW 29x8 [M4] GW / N38 - magnetic holder rubber internal thread

properties
properties values
Cat. no. 160305
GTIN/EAN 5906301813637
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 29 mm [±1 mm]
Height 8 mm [±1 mm]
Weight 18 g
Load capacity ~ ? 6.40 kg / 62.76 N
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics UMGGW 29x8 [M4] GW / N38 - magnetic holder rubber internal thread
properties values units
remenance Br [min. - max.] ? 12.2-12.6 kGs
remenance Br [min. - max.] ? 1220-1260 mT
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

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

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: 160305-2026
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Thanks to the use of flexible Santoprene rubber coating, these holders do not scratch paint and ensure stability even on slippery surfaces. They are commonly used in the advertising industry (car wrapping, foil fixing), lighting (LED work lamps), and mobile monitoring. 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 recommended choice for mounting on a car roof, because you can be sure that rusty stains will not appear on the paint after rain.
Although rubber creates a small distance reducing perpendicular pull-off force, it drastically increases resistance when trying to slide the magnet across the surface. Thanks to this, these magnets hold onto the car roof excellently even at high speeds and wind resistance. They ensure safety 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.
Most rubberized holders use a special multi-pole system (often close to a Halbach array) on a steel base. Field concentration allows achieving high holding force 6.40 kg despite the distance created by the rubber layer.

Advantages as well as disadvantages of rare earth magnets.

Advantages

Besides their exceptional field intensity, neodymium magnets offer the following advantages:
  • Their magnetic field is durable, and after approximately 10 years it drops only by ~1% (according to research),
  • They feature excellent resistance to magnetism drop as a result of external fields,
  • The use of an metallic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
  • They are known for high magnetic induction at the operating surface, which affects their effectiveness,
  • Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
  • Thanks to versatility in forming and the ability to adapt to individual projects,
  • Wide application in future technologies – they are commonly used in HDD drives, brushless drives, precision medical tools, as well as modern systems.
  • Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which allows their use in miniature devices

Weaknesses

Disadvantages of neodymium magnets:
  • At strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
  • We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 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 secure oxidation as well as corrosion.
  • We suggest a housing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complicated forms.
  • Possible danger related to microscopic parts of magnets are risky, if swallowed, which becomes key in the context of child health protection. Additionally, small elements of these magnets are able to complicate diagnosis medical when they are in the body.
  • High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Holding force characteristics

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The specified lifting capacity concerns the limit force, measured under optimal environment, meaning:
  • with the use of a yoke made of special test steel, ensuring full magnetic saturation
  • whose thickness is min. 10 mm
  • with a surface cleaned and smooth
  • with zero gap (without coatings)
  • for force applied at a right angle (in the magnet axis)
  • at temperature approx. 20 degrees Celsius

Key elements affecting lifting force

Bear in mind that the application force will differ depending on elements below, in order of importance:
  • Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
  • Load vector – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
  • Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through 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 increases field saturation. Uneven metal weaken the grip.
  • Temperature influence – hot environment weakens pulling force. Too high temperature can permanently damage the magnet.

Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance between the magnet’s surface and the plate decreases the lifting capacity.

Precautions when working with NdFeB magnets
Pinching danger

Pinching hazard: The pulling power is so immense that it can cause hematomas, crushing, and broken bones. Use thick gloves.

Risk of cracking

Despite the nickel coating, neodymium is brittle and cannot withstand shocks. Avoid impacts, as the magnet may crumble into sharp, dangerous pieces.

Choking Hazard

Only for adults. Small elements can be swallowed, leading to severe trauma. Keep out of reach of children and animals.

Data carriers

Equipment safety: Neodymium magnets can damage payment cards and delicate electronics (heart implants, hearing aids, timepieces).

Allergic reactions

Some people experience a contact allergy to Ni, which is the standard coating for NdFeB magnets. Prolonged contact might lead to an allergic reaction. We recommend use protective gloves.

Immense force

Before starting, read the rules. Sudden snapping can destroy the magnet or hurt your hand. Be predictive.

Flammability

Fire warning: Rare earth powder is explosive. Do not process magnets without safety gear as this risks ignition.

Danger to pacemakers

Life threat: Neodymium magnets can turn off heart devices and defibrillators. Do not approach if you have electronic implants.

Keep away from electronics

Be aware: neodymium magnets generate a field that interferes with sensitive sensors. Maintain a safe distance from your phone, tablet, and navigation systems.

Thermal limits

Monitor thermal conditions. Exposing the magnet above 80 degrees Celsius will ruin its properties and strength.

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