Neodymium Cylinder Magnet – 4mm x 5mm | N45

The Neodymium Cylinder Magnet – 4mm x 5mm | N45 is a miniature rare earth permanent magnet measuring 4mm in diameter x 5mm long. Manufactured from N45 grade Neodymium Iron Boron (NdFeB), this compact cylindrical magnet provides high magnetic performance relative to its very small physical size, making it suitable for precision product assemblies, sensors, instrumentation, electronics, magnetic closures, models, prototypes and custom OEM applications.

With a 4mm diameter and 5mm length, this N45 neodymium cylinder magnet has a compact rod-style profile that can be incorporated into appropriately sized circular recesses, housings and small mechanical components where installation space is limited.

Also known as a 4mm neodymium rod magnet, N45 rare earth cylinder magnet, NdFeB cylinder magnet, miniature cylindrical magnet or small magnetic rod, it provides permanent magnetic operation without electricity, batteries or charging.

Key Features

• Diameter: 4mm
• Length: 5mm
• Shape: Cylinder / Rod
• Magnetic material: Neodymium Iron Boron (NdFeB)
• Magnetic grade: N45
• Rare earth permanent magnet
• Miniature cylindrical profile
• High magnetic performance relative to size
• Suitable for small circular recesses and housings
• Useful for precision product assemblies
• Suitable for sensors and instrumentation
• Useful for magnetic closures and positioning
• Suitable for models, prototypes and OEM products
• Permanent magnetic operation
• No electricity, batteries or charging required

Common Applications

• Miniature product assemblies
• Engineering
• Manufacturing
• Electronics
• Sensors and instrumentation
• Position detection
• Proximity sensing
• Magnetic switching
• Small magnetic closures
• Precision mechanisms
• Models and miniatures
• Scientific equipment
• Research and development
• Prototype devices
• Custom magnetic assemblies
• OEM products

4mm Diameter x 5mm Long Cylinder Magnet

This neodymium cylinder magnet measures 4mm in diameter x 5mm long, providing a very compact cylindrical form.

Its miniature dimensions can make it suitable for integration into:

• Small circular recesses
• Compact product housings
• Electronic assemblies
• Sensor systems
• Precision mechanisms
• Models
• Magnetic closures
• Prototype products

Where installed into a recess or housing, provide appropriate dimensional clearance and avoid force-fitting the brittle neodymium magnetic material.

N45 Grade Neodymium Iron Boron

This cylinder magnet is manufactured from N45 grade Neodymium Iron Boron (NdFeB).

N45 is a high-performance neodymium magnetic grade used where strong magnetic properties are required from compact physical dimensions.

The N45 designation identifies the magnetic material grade. It does not directly specify the finished magnet's:

• Pull force
• Holding capacity
• Surface Gauss
• Safe working load

The practical performance of the finished 4mm x 5mm cylinder magnet depends on its geometry, magnetisation direction, magnetic circuit and application conditions in addition to the N45 material grade.

Miniature Product Assemblies

The compact dimensions of this N45 cylinder magnet make it suitable for appropriately designed miniature products and components.

Potential applications include:

• Small enclosures
• Removable components
• Miniature catches
• Precision mechanisms
• Models
• Instruments
• Electronic devices
• Prototype products

Depending on the design, the magnet may attract suitable ferromagnetic steel or another appropriately oriented permanent magnet.

Sensors and Instrumentation

Small neodymium cylinder magnets can be incorporated into appropriately designed magnetic sensing systems.

Potential applications include:

• Reed switch activation
• Hall-effect sensing
• Position detection
• Proximity sensing
• Magnetic switching
• Instrumentation
• Automation
• Electronic prototypes

The magnetisation direction and pole orientation have not been supplied for this product.

Where magnetic field direction is critical to sensor operation, confirm the required magnetisation specification before installation.

Small Magnetic Closures

The compact 4mm x 5mm dimensions can also make this magnet useful for miniature magnetic closure systems.

Potential applications include:

• Small boxes
• Product enclosures
• Models
• Display components
• Lightweight covers
• Precision products
• Custom assemblies

The magnet may be paired with compatible ferromagnetic steel or another permanent magnet.

For magnet-to-magnet closures, confirm polarity and orientation before permanently bonding the magnets into position.

Magnetisation Direction

Cylinder magnets can be manufactured with different magnetisation configurations.

Depending on manufacture, a cylinder magnet may be magnetised:

• Axially along its length
• Diametrically across its diameter
• In another application-specific configuration

The magnetisation direction for this 4mm x 5mm N45 cylinder magnet has not been supplied and should not be assumed.

This is particularly important for:

• Hall-effect sensors
• Reed switches
• Magnetic encoders
• Magnet-to-magnet assemblies
• Engineered magnetic circuits

Confirm magnetisation direction and polarity before permanent installation where field orientation is important.

Magnetic Performance

Actual magnetic performance depends on factors including:

• N45 neodymium grade
• Magnetisation direction
• Magnet geometry
• Magnetic circuit design
• Target steel composition
• Target steel thickness
• Available contact area
• Surface condition
• Air gaps
• Paint and coatings
• Load direction

No specific pull force or magnetic flux density in Gauss has been supplied for this magnet and these values should not be inferred from the N45 grade or dimensions alone.

Air Gaps and Small Magnets

Air gaps can have a particularly noticeable effect on the performance of miniature neodymium magnets.

Magnetic attraction can be reduced by separation created by:

• Paint
• Adhesive
• Plastic
• Protective films
• Coatings
• Dirt
• Rust
• Mechanical clearance
• Uneven surfaces

Because this magnet is only 4mm in diameter x 5mm long, even a relatively small separation can significantly affect practical magnetic performance.

Minimise unnecessary air gaps wherever practical.

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 a compatible steel surface.

Shear loading occurs when a load acts parallel to the surface and encourages the magnet to slide.

Practical shear holding can be considerably lower than direct-pull performance and depends heavily on:

• Surface friction
• Installation geometry
• Contact area
• Surface coatings
• Vibration
• Mechanical leverage

Test the magnet in its intended application where magnetic holding is important.

Bonding a Small Neodymium Cylinder Magnet

This 4mm x 5mm cylinder magnet may be bonded into an appropriately sized recess or housing.

Before bonding:

• Confirm polarity and magnetisation orientation
• Clean the bonding surfaces
• Remove oil, grease and contamination
• Select an adhesive compatible with the actual magnet surface
• Provide suitable dimensional clearance
• Avoid force-fitting
• Allow the adhesive to cure according to its instructions

The specific coating or plating has not been supplied, so adhesive compatibility with the actual magnet surface should be confirmed before permanent installation.

Avoid Force-Fitting Neodymium Magnets

Neodymium magnetic material is hard and brittle.

Do not press this magnet forcefully into an undersized recess, as excessive mechanical pressure may cause it to:

• Chip
• Crack
• Fracture
• Damage its surface finish

A correctly sized recess with appropriate clearance and a suitable bonding method is generally preferable to a force fit.

Compatible Target Materials

Neodymium magnets attract suitable ferromagnetic materials, including:

• Mild steel
• Iron
• Magnetic steel
• Compatible ferromagnetic components

They will not effectively attract non-magnetic materials such as:

• Aluminium
• Copper
• Brass
• Plastic
• Timber
• Glass

Many stainless steel grades may be weakly magnetic or non-magnetic and should be tested before relying on magnetic attraction.

Neodymium vs Ferrite Cylinder Magnets

Neodymium and ferrite magnets offer different characteristics.

Neodymium cylinder magnets generally provide:

• Higher magnetic performance relative to size
• Strong magnetic properties from compact dimensions
• Advantages for miniature and space-constrained applications
• Broad suitability for sensors, engineering and precision assemblies

Ferrite magnets are generally:

• More economical
• Naturally corrosion resistant
• Suitable for many general-purpose applications
• Often used where larger physical dimensions are acceptable

An N45 neodymium cylinder magnet can be particularly useful where available installation space is restricted and strong magnetic properties are required from a miniature component.

Permanent Magnetic Operation

This N45 neodymium cylinder 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

• Product Type: Neodymium Cylinder Magnet
• Alternative Names: Neodymium Rod Magnet, N45 Rare Earth Cylinder Magnet, NdFeB Cylinder Magnet, Miniature Cylindrical Magnet, Magnetic Rod
• Diameter: 4mm
• Length: 5mm
• Shape: Cylinder / Rod
• Magnetic Material: Neodymium Iron Boron (NdFeB)
• Magnetic Grade: N45
• Magnet Type: Rare Earth Permanent Magnet
• Magnetic Operation: Permanent
• Power Required: None
• Target Materials: Compatible ferromagnetic iron and steel
• Primary Functions: Magnetic attraction, sensing, positioning, closure and product integration
• Typical Applications: Electronics, engineering, sensors, instrumentation, miniature product assemblies, models, prototypes and OEM products

Safety and Handling

Neodymium magnets can attract other magnets and ferromagnetic objects unexpectedly.

Handle this miniature cylinder magnet carefully and avoid uncontrolled collisions with other magnets or steel objects.

Neodymium magnetic material is brittle and may chip, crack or fragment when subjected to impact or excessive mechanical stress.

Do not:

• Drill
• Cut
• Grind
• Machine
• Crush
• Force-fit the magnet

Keep neodymium magnets an appropriate distance from:

• Pacemakers
• Implanted medical devices
• Magnetic storage media
• Magnetic cards
• Sensitive electronic equipment

This 4mm x 5mm neodymium magnet presents a serious ingestion hazard and must be kept securely away from babies and children.

Swallowed magnets can cause severe or life-threatening internal injuries. Multiple swallowed magnets, or a magnet swallowed together with another metal object, can attract through intestinal tissue and cause perforation, blockage or other serious injuries.

Seek urgent medical attention if magnet ingestion is suspected.

If incorporated into another product, ensure the magnet is securely retained so it cannot become detached during normal or reasonably foreseeable use.

Please Note

This product is an N45 Neodymium Cylinder Magnet measuring 4mm in diameter x 5mm long, manufactured from Neodymium Iron Boron (NdFeB) rare earth magnetic material.

No specific pull force, Gauss rating, coating or plating, magnetisation direction, pole orientation, dimensional tolerance or maximum operating temperature has been supplied and these specifications should not be assumed.

Actual magnetic performance depends on the N45 magnetic material, magnetisation direction, magnetic circuit, target steel composition and thickness, available contact area, air gaps, surface condition and operating conditions.

The N45 grade identifies the magnetic material grade and does not represent the finished magnet's pull force, lifting capacity or safe working load.

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