Neodymium Disc Magnet 20mm x 4mm N42
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Neodymium Disc Magnet – 20mm x 4mm | N42
The Neodymium Disc Magnet – 20mm x 4mm | N42 is a premium rare earth disc magnet designed to deliver exceptional magnetic strength in a slim, low-profile design. Manufactured from high-quality N42 grade neodymium (NdFeB), this permanent magnet provides powerful holding force and outstanding reliability, making it ideal for industrial, commercial, engineering, manufacturing, educational, and DIY applications.
Measuring 20mm in diameter and 4mm thick, this precision-engineered disc magnet offers an excellent balance between surface contact area and compact thickness. Its larger diameter provides a broad magnetic contact surface, making it suitable for magnetic closures, display systems, fixtures, product assembly, automation equipment, signage, and countless custom magnetic solutions.
The magnet is axially magnetised through its 4mm thickness, with the north and south poles located on the two flat circular faces. This configuration creates a concentrated magnetic field that delivers consistent holding performance against ferrous materials while allowing easy integration into compact assemblies and engineered products.
Protected by a durable nickel (Ni-Cu-Ni) triple-layer coating, the magnet offers excellent resistance to corrosion and everyday wear while maintaining a bright, polished finish. Whether you're developing new products, building magnetic fixtures, or replacing existing magnets, the 20mm x 4mm N42 Neodymium Disc Magnet provides reliable, long-lasting magnetic performance.
Key Features
- Premium N42 grade neodymium rare earth magnet
- 20mm diameter x 4mm thickness
- High-strength permanent magnet
- Slim disc profile with a large magnetic contact area
- Axially magnetised through the thickness
- Durable nickel (Ni-Cu-Ni) plated finish
- Excellent resistance to corrosion in indoor environments
- Long-lasting magnetic performance
- Precision manufactured for consistent quality
- Suitable for industrial, commercial, and DIY applications
Common Applications
- Magnetic cabinet catches
- Product displays
- Retail signage
- Engineering fixtures and jigs
- Industrial automation
- Robotics projects
- Sensor mounting
- Magnetic closures
- Prototype development
- Workshop organisation
Ideal For
- Engineers
- OEM manufacturers
- Product designers
- Automation specialists
- Sign manufacturers
- Maintenance technicians
- Research laboratories
- Educational institutions
- Makers and hobbyists
- DIY enthusiasts
Why Choose an N42 Neodymium Disc Magnet?
Neodymium magnets are the strongest commercially available permanent magnets, allowing compact components to produce exceptional holding force. The N42 grade offers an excellent combination of magnetic performance, durability, and versatility, making it one of the most popular choices for industrial and commercial applications.
The 20mm diameter provides a generous magnetic contact area, while the 4mm thickness allows the magnet to be integrated into applications where space is limited. This makes it ideal for magnetic fastening, positioning, clamping, and product assembly where a slim but powerful magnet is required.
Finished with a corrosion-resistant nickel coating, this magnet is built for reliable long-term performance in indoor environments. Its precision manufacturing and consistent magnetic properties make it an excellent choice for OEM production, engineering projects, scientific research, and custom magnetic assemblies.
Technical Specifications
- Product Type: Neodymium Disc Magnet
- Material: Neodymium (NdFeB)
- Magnet Grade: N42
- Shape: Disc
- Diameter: 20mm
- Thickness: 4mm
- Magnetisation: Axially Magnetised (through the 4mm thickness)
- Coating: Nickel (Ni-Cu-Ni)
- Reusable: Yes
- Application: Holding, positioning, fastening, sensing, display systems, and magnetic assemblies
Please Note
Neodymium magnets are extremely powerful for their size and should be handled carefully. They can attract steel objects or other magnets with significant force, creating pinch hazards and potentially causing the magnet to chip if allowed to collide.
Actual magnetic holding performance will vary depending on the thickness and condition of the mating steel surface, air gap, alignment, operating temperature, and the direction of the applied force.
Keep this magnet away from children, pacemakers, medical implants, magnetic storage media, and sensitive electronic devices.
Neodymium magnets are hard but brittle and should not be drilled, cut, machined, or subjected to excessive impact after manufacture. For optimal performance and longevity, avoid exposing the magnet to temperatures beyond the recommended operating range for N42 grade neodymium magnets.
Typical Physical Properties
NB: Ranges are indicative for product category, please check individual products for specic values within that range.
Production Flow Diagram
Demagnetization Curves
Surface Treatment
The most common coating for Neodymium magnets is Nickel + Copper + Nickel (Ni + Cu + Ni). This coating offers the magnet relatively good protection from corrosion and passive applications. If the magnet will be exposed to moisture or liquid then consider the use of an organic coating such as Epoxy. A hard wearing coating, Epoxy is suited to applications where the magnet will come under some friction or knocking.
Range and Tolerance
Magnets are readily available in Blocks, Discs, Cylinders & Rings. We specializes in the supply of short-run prototype magnets including Arc Segments, various magnetic orientations etc. If you need a magnet size that we don't carry in stock, submit a Design-a-Magnet enquiry for a quote on your custom magnet design.
Magnetic Properties
Neodymium magnets are offered in several different grades. The first section N30-54 has an operating temperature of up to 80 degrees. Most of our stock only goes up to N38. The second section, denoted with the "M" prefix after the grade has an operating temperature 100 degrees. After this the grades are "H", "SH", "UH" & "EH". In order for the magnet to withstand a higher operating temperature, during production more of the raw material PrNd is incorporated as these elements have a naturally occurring resistance to high temperatures.
Returns Policy
If you are not entirely satisfied with your purchase, we're here to help.
We have a 30 Day Returns policy at Frenergy Magnets. You may return your item within 30 days of receiving it to receive a refund.
The product/s must be unused and in the same condition you received them in. Please contact us at info@frenergy.com.au to initiate the returns process.
The buyer is responsible for the cost of returning the order.
