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

magnetic holder rubber internal thread

Catalog no 160305

GTIN: 5906301813637

5.00

Diameter Ø

29 mm [±1 mm]

Height

8 mm [±1 mm]

Weight

18 g

Load capacity

6.40 kg / 62.76 N

8.61 ZŁ with VAT / pcs + price for transport

7.00 ZŁ net + 23% VAT / pcs

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Carbon Footprint – environmental impact GPSR Regulation – product safety

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Pick up the phone and ask +48 888 99 98 98 or contact us using contact form the contact form page.
Lifting power along with structure of a neodymium magnet can be checked with our online calculation tool.

Orders placed before 14:00 will be shipped the same business day.

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	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	T
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

properties	values	units
Vickers hardness	≥550	Hv
Density	≥7.4	g/cm³
Curie Temperature TC	312 - 380	°C
Curie Temperature TF	593 - 716	°F
Specific resistance	150	μΩ⋅Cm
Bending strength	250	Mpa
Compressive strength	1000~1100	Mpa
Thermal expansion parallel (∥) to orientation (M)	(3-4) x 106	°C^-1
Thermal expansion perpendicular (⊥) to orientation (M)	-(1-3) x 10-6	°C^-1
Young's modulus	1.7 x 104	kg/mm²

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MW 3x1 / N38 - cylindrical magnet

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UMT 29x38 white / N38 - board holder

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UMH 32x8x46 [M6] / N38 - magnetic holder with hook

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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 quick disassembly 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 tight 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 durability. 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 maximum stability of mounting under vibrations, which is crucial in transport and automotive.

The standard metric thread allows easy integration with most accessories available on the market. This enables quick creation of a mobile mounting point for work lighting, reversing cameras, sensors, or advertising boards.

Most rubberized holders use a special multi-pole system (often close to a Halbach array) on a steel base. This is much safer for electronics inside the vehicle (e.g., under the roof) compared to regular magnets.

Advantages and disadvantages of neodymium magnets.

Benefits

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

Their power is maintained, and after around ten years it drops only by ~1% (theoretically),
Neodymium magnets are distinguished by extremely resistant to demagnetization caused by magnetic disturbances,
A magnet with a shiny nickel surface looks better,
The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
Due to the possibility of accurate forming and adaptation to unique needs, neodymium magnets can be modeled in a wide range of shapes and sizes, which makes them more universal,
Key role in innovative solutions – they serve a role in hard drives, motor assemblies, advanced medical instruments, and multitasking production systems.
Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages

Disadvantages of NdFeB magnets:

To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
Due to limitations in creating threads and complicated forms in magnets, we propose using cover - magnetic mechanism.
Health risk to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small elements of these products can disrupt the diagnostic process medical in case of swallowing.
High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Lifting parameters

Detachment force of the magnet in optimal conditions – what contributes to it?

Holding force of 6.40 kg is a measurement result conducted under standard conditions:

on a base made of structural steel, perfectly concentrating the magnetic flux
with a cross-section minimum 10 mm
characterized by smoothness
without any insulating layer between the magnet and steel
for force applied at a right angle (pull-off, not shear)
at temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

Bear in mind that the working load will differ influenced by the following factors, in order of importance:

Air gap (betwixt the magnet and the metal), since even a tiny distance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of nominal force).
Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
Material composition – not every steel reacts the same. High carbon content weaken the attraction effect.
Surface condition – ground elements ensure maximum contact, which increases force. Rough surfaces weaken the grip.
Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

Lifting capacity was determined with the use of a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance between the magnet’s surface and the plate lowers the load capacity.

Safety rules for work with NdFeB magnets

Safe distance

Intense magnetic fields can corrupt files on credit cards, hard drives, and storage devices. Maintain a gap of min. 10 cm.

Dust explosion hazard

Fire hazard: Rare earth powder is highly flammable. Do not process magnets in home conditions as this risks ignition.

Safe operation

Use magnets with awareness. Their powerful strength can shock even experienced users. Stay alert and do not underestimate their power.

Finger safety

Large magnets can smash fingers instantly. Never put your hand between two attracting surfaces.

Nickel coating and allergies

Some people experience a contact allergy to Ni, which is the standard coating for neodymium magnets. Prolonged contact might lead to skin redness. It is best to wear safety gloves.

Choking Hazard

NdFeB magnets are not toys. Swallowing a few magnets may result in them attracting across intestines, which constitutes a direct threat to life and necessitates immediate surgery.

Compass and GPS

Be aware: neodymium magnets produce a field that confuses sensitive sensors. Maintain a separation from your phone, tablet, and navigation systems.

Beware of splinters

Despite metallic appearance, the material is brittle and cannot withstand shocks. Do not hit, as the magnet may crumble into hazardous fragments.

Operating temperature

Watch the temperature. Heating the magnet above 80 degrees Celsius will destroy its magnetic structure and strength.

ICD Warning

Warning for patients: Powerful magnets disrupt medical devices. Keep minimum 30 cm distance or request help to handle the magnets.

Safety First! Want to know more? Check our post: Are neodymium magnets dangerous?

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

Do you have trouble choosing?

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

Magnetic properties of material N38

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Pulling Force

Magnetic Induction

See also products

SM 25x325 [2xM8] / N52 - magnetic separator

MW 3x1 / N38 - cylindrical magnet

UMT 29x38 white / N38 - board holder

UMH 32x8x46 [M6] / N38 - magnetic holder with hook

Advantages and disadvantages of neodymium magnets.

Benefits

Disadvantages

Lifting parameters

Detachment force of the magnet in optimal conditions – what contributes to it?

Impact of factors on magnetic holding capacity in practice

Safe distance

Dust explosion hazard

Safe operation

Finger safety

Nickel coating and allergies

Choking Hazard

Compass and GPS

Beware of splinters

Operating temperature

ICD Warning

Physical properties of sintered neodymium magnets Nd₂Fe₁₄B at 20°C