Neodymium Ring Magnet – 70mm OD x 3mm H | 14mm Hole | N42

Description

The Neodymium Ring Magnet – 70mm Outer Diameter x 3mm Height with a 14mm Centre Hole | N42 is a powerful, low-profile rare earth magnet designed for industrial, engineering and custom magnetic applications requiring a large circular magnetic surface with a central mounting opening.

Manufactured from N42 grade Neodymium Iron Boron (NdFeB), this permanent ring magnet features a 70mm outer diameter, 14mm inner hole diameter and 3mm thickness. Its wide, flat design provides a substantial annular magnetic surface while maintaining a slim profile, making it suitable for integration into mechanical assemblies, magnetic holding systems, positioning devices and custom equipment.

The 14mm central hole provides clearance for suitable shafts, rods, fasteners or other components, depending on the installation requirements. This allows the magnet to be incorporated into assemblies where a central opening is required without drilling or modifying the brittle magnetic material.

N42 neodymium magnets offer high magnetic energy density compared with conventional ferrite magnets, delivering strong magnetic performance relative to their size. Their permanent magnetic properties make them useful for applications requiring continuous magnetic attraction without electricity or batteries.

Ideal for engineering, manufacturing, magnetic positioning, industrial equipment, product development, magnetic retention and OEM assemblies, this large-diameter neodymium ring magnet offers a versatile solution for specialised magnetic applications.

Also known as a 70mm neodymium ring magnet, N42 rare earth ring magnet, 70mm OD magnet with 14mm hole, flat neodymium washer magnet or circular NdFeB ring magnet, this product is designed for applications where magnetic performance and a low-profile ring geometry are important.

Key Features

• Outer Diameter (OD): 70mm

• Inner Diameter (ID): 14mm

• Height / Thickness: 3mm

• Magnetic Grade: N42

• Material: Neodymium Iron Boron (NdFeB)

• Shape: Flat circular ring

• Magnet Type: Rare Earth Permanent Magnet

• Large 70mm outer diameter

• Central 14mm through-hole

• Slim 3mm profile

• High magnetic energy density

• Suitable for custom magnetic assemblies

• Useful for industrial and engineering applications

• Can accommodate compatible central mounting components

• Permanent magnetic operation without external power

• Suitable for magnetic positioning and retention systems

Common Applications

This N42 neodymium ring magnet may be suitable for:

• Industrial machinery and equipment

• Custom magnetic assemblies

• Engineering projects

• Magnetic positioning systems

• Magnetic retention devices

• Mechanical fixtures and jigs

• Equipment housings

• Product development

• Research and development

• Prototype assemblies

• OEM manufacturing

• Magnetic coupling concepts

• Circular alignment systems

• Shaft-mounted magnetic assemblies

• Magnetic holding applications

• Laboratory equipment

Application suitability depends on the magnetisation direction, installation geometry, magnetic circuit and required holding performance.

N42 Grade Neodymium Ring Magnet

This ring magnet is manufactured from N42 grade Neodymium Iron Boron, a high-performance rare earth magnetic material.

Neodymium magnets provide high magnetic energy density compared with many traditional permanent magnet materials, allowing strong magnetic fields to be generated from relatively compact components.

What Does N42 Mean?

N42 identifies the magnetic material's energy classification.

The designation relates to the maximum energy product of the NdFeB material and helps distinguish it from other neodymium grades.

N42 does not mean this magnet has a 42kg pull force.

Actual magnetic holding strength depends on the magnet's dimensions, magnetisation direction, target material, magnetic circuit and operating conditions.

Large 70mm Diameter with Slim 3mm Profile

The combination of a 70mm outer diameter and 3mm thickness creates a wide, flat ring magnet.

This geometry may be useful for applications where:

• A broad circular magnetic component is required

• Installation space is limited in height

• A low-profile magnetic assembly is preferred

• A central opening is needed

• A ring-shaped magnetic component must fit within a larger mechanism

The magnet's relatively thin cross-section should be considered during installation, as neodymium magnets are brittle and may fracture under bending, impact or uneven mechanical pressure.

14mm Centre Hole for Assembly Integration

The 14mm diameter centre hole provides an opening through the magnet.

Depending on the application, this opening may accommodate:

• Compatible shafts

• Rods

• Bolts

• Spacers

• Bushings

• Alignment components

• Custom mounting hardware

The centre hole is a straight opening rather than a confirmed countersunk fixing feature.

When mounting the magnet, avoid applying concentrated mechanical pressure directly to the brittle magnetic material.

For applications involving fasteners or shafts, provide suitable clearance and use an appropriate mounting arrangement.

Magnetic Holding and Retention

Neodymium ring magnets can be incorporated into magnetic holding systems where their geometry and magnetic performance are suitable.

Potential applications include:

• Removable equipment components

• Magnetic closures

• Custom fixtures

• Positioning assemblies

• Equipment covers

• Magnetic retention systems

Holding performance depends on the magnetic pole arrangement, target material, contact conditions and installation geometry.

For applications involving vibration, shock or moving equipment, the complete assembly should be tested under realistic operating conditions.

Magnetic Positioning and Alignment

The circular geometry and central opening of this magnet may make it useful in custom positioning and alignment systems.

Potential functions include:

• Locating circular components

• Aligning mechanical assemblies

• Retaining removable parts

• Assisting repetitive positioning

• Integrating magnetic attraction into specialised equipment

The suitability of this magnet for precision positioning depends on its actual magnetisation direction, dimensional tolerances and magnetic field characteristics.

Magnetisation Direction

Neodymium ring magnets can be manufactured with different magnetic orientations.

Common configurations include:

• Axial magnetisation: North and south poles are located on the opposing flat circular faces.

• Diametrical magnetisation: Magnetic polarity is oriented across the diameter of the ring.

The actual magnetisation direction of this product has not been specified and should be confirmed before use in applications requiring a particular pole orientation.

Magnetisation direction is especially important when designing magnetic couplings, alignment systems or assemblies containing multiple magnets.

Magnetic Performance

The practical magnetic performance of this N42 ring magnet depends on:

• Magnetic material properties

• Outer diameter

• Inner diameter

• Thickness

• Magnetisation direction

• Pole configuration

• Magnetic circuit design

• Target material

• Target steel thickness

• Contact area

• Surface condition

• Air gaps

• Operating temperature

• Load direction

No specific pull force or surface Gauss rating has been supplied.

These values should not be inferred from the N42 designation alone.

Direct Pull vs Shear Force

Magnetic holding performance varies according to the direction of the applied load.

Direct pull occurs when the magnet is separated perpendicular to the attracting surface.

Shear loading occurs when the magnet is encouraged to slide parallel to the target surface.

Shear performance may be influenced by surface friction, coatings, air gaps, vibration and mechanical leverage.

Where the magnet is used for holding or retention, performance should be tested under the actual operating conditions.

Air Gaps Reduce Magnetic Attraction

Magnetic attraction decreases as the distance between the magnet and target increases.

Potential sources of air gaps include:

• Adhesive

• Paint

• Powder coating

• Plastic housings

• Protective films

• Mechanical clearance

• Surface irregularities

For applications requiring maximum magnetic interaction, unnecessary separation should be minimised.

Bonding and Installation

Adhesive bonding or installation within a suitably designed housing may be appropriate for this ring magnet.

Before installation:

1. Confirm the magnetisation direction and polarity.

2. Check the intended magnetic arrangement.

3. Clean the bonding surfaces.

4. Remove dust, oil and grease.

5. Select an adhesive compatible with the magnet's actual coating.

6. Confirm suitability for the expected operating temperature.

7. Provide appropriate clearance around the 14mm centre hole.

8. Avoid force-fitting or excessive clamping pressure.

9. Allow the adhesive to cure according to the manufacturer's instructions.

The exact coating or plating has not been supplied, so adhesive compatibility should be confirmed before permanent installation.

For safety-critical applications, suitable engineered mechanical retention may also be required.

Avoid Mechanical Stress

Neodymium Iron Boron is a hard but brittle magnetic material.

This ring magnet has a relatively thin 3mm profile, making careful handling especially important.

Avoid:

• Dropping the magnet

• Allowing magnets to collide

• Bending or flexing

• Applying uneven pressure

• Overtightening fasteners

• Force-fitting into housings

• Concentrating pressure around the centre hole

Excessive mechanical stress may cause chipping, cracking or fracture.

Do Not Machine Neodymium Magnets

Finished neodymium magnets should not normally be mechanically modified.

Avoid drilling, cutting, grinding, filing or machining the magnet.

These processes can damage the brittle NdFeB material and any protective coating.

If a different hole diameter, thickness or ring size is required, select a magnet manufactured to the required dimensions.

Compatible Magnetic Materials

Neodymium magnets attract suitable ferromagnetic materials, including:

• Iron

• Mild steel

• Magnetic steel

• Compatible ferromagnetic components

They do not effectively attract inherently non-magnetic materials such as:

• Aluminium

• Copper

• Brass

• Plastic

• Timber

• Glass

Many stainless steel grades may also be weakly magnetic or non-magnetic.

Test the intended target material where magnetic compatibility is important.

N42 Neodymium vs Ferrite Ring Magnets

Neodymium magnets generally provide higher magnetic energy density than conventional ferrite magnets.

N42 neodymium may be preferred for:

• Compact magnetic assemblies

• Strong magnetic performance relative to size

• Engineering components

• Custom fixtures

• Magnetic retention systems

• Specialised industrial equipment

Ferrite magnets may be preferred for:

• More economical applications

• Larger magnetic components

• Applications benefiting from natural corrosion resistance

• Designs where lower magnetic energy density is acceptable

The appropriate magnetic material depends on the required performance, environment and design constraints.

Permanent Magnetic Operation

This N42 ring magnet is a permanent magnet.

It requires:

• No electricity

• No batteries

• No charging

• No external power supply

Its magnetic field remains continuously active during normal use.

Technical Specifications

Compliance & Safety

Pinch Hazards: Neodymium magnets can attract rapidly and forcefully to other magnets and ferromagnetic objects. Keep fingers and skin clear of contact points.

Brittle Material: Neodymium Iron Boron is hard but brittle. Magnets can chip, crack or fracture if dropped, struck or allowed to collide.

Thin Profile: The 3mm thickness requires careful handling. Avoid bending, uneven loading or concentrated mechanical pressure.

Flying Fragments: Broken magnets may produce sharp fragments. Use appropriate protective equipment when handling powerful magnets.

Do Not Machine: Avoid drilling, cutting, grinding or modifying the magnet.

Medical Devices: Keep magnets at an appropriate distance from pacemakers, implanted medical devices and magnetically sensitive equipment.

Children: Keep magnets securely away from babies and children. Swallowed magnets can cause severe internal injuries and require urgent medical attention.

Lifting Applications: This magnet is not certified lifting equipment and must not be used for overhead or safety-critical lifting.

Frequently Asked Questions

What size is this neodymium ring magnet?

This magnet has a 70mm outer diameter, 14mm centre hole diameter and 3mm thickness.

What does N42 mean?

N42 identifies the magnetic material grade of the Neodymium Iron Boron magnet. It relates to the material's magnetic energy classification rather than its pull force.

Does N42 mean the magnet has a 42kg pull force?

No. N42 identifies the magnetic grade and does not indicate a 42kg pull force or lifting capacity.

Is this magnet axially magnetised?

The magnetisation direction has not been supplied and should be confirmed before use in applications requiring a specific magnetic orientation.

Can I put a bolt through the 14mm centre hole?

The 14mm opening may accommodate compatible mounting hardware, but the installation must avoid excessive pressure on the brittle magnet. Confirm clearances and use an appropriate mounting arrangement.

Is the centre hole countersunk?

A countersunk hole has not been specified. The product is described as having a 14mm centre hole.

Can this ring magnet be used for industrial applications?

It may be suitable for industrial machinery, positioning systems, fixtures and engineered assemblies where its dimensions and magnetic properties meet the application requirements.

Can I glue this magnet into a housing?

Adhesive bonding may be suitable, provided the adhesive and installation method are compatible with the magnet's actual coating and operating conditions.

Can this magnet be drilled or cut?

No. Neodymium is brittle and should not be drilled, cut, ground or machined.

Will this magnet attract stainless steel?

It depends on the stainless steel grade. Some stainless steels are ferromagnetic, while others are weakly magnetic or non-magnetic.

Related Products

Customers considering this product may also be interested in:

• Neodymium Ring Magnets

• N42 Neodymium Magnets

• Neodymium Disc Magnets

• Neodymium Block Magnets

• Rare Earth Pot Magnets

• High-Temperature Neodymium Magnets

• Custom-Made Magnets

Please Note

The Neodymium Ring Magnet – 70mm OD x 3mm H | 14mm Hole | N42 is manufactured from N42 grade Neodymium Iron Boron.

Its dimensions are:

• Outer diameter: 70mm

• Centre hole diameter: 14mm

• Thickness: 3mm

The N42 designation identifies the magnetic material grade and does not mean this magnet has a 42kg pull force.

No specific pull force, surface Gauss rating, coating or plating, magnetisation direction, pole configuration, dimensional tolerance or maximum operating temperature has been supplied.

Actual magnetic performance depends on the magnetisation configuration, magnetic circuit, target material, target steel thickness, contact area, air gaps, load direction and installation geometry.

Neodymium is a hard and brittle magnetic material. The thin 3mm profile requires careful handling to avoid cracking or fracture.

This magnet is not certified lifting equipment and should not be used for overhead or safety-critical lifting.