3" x 1/2" N42 Neodymium Disc Magnets with 1/4" Center Hole – Strong Rare Earth Magnets
Quick Facts
| Attribute |
Value |
| Magnet Type |
Neodymium Rare Earth Disc Magnet |
| Grade |
N42 |
| Shape |
Disc with Center Hole |
| Diameter |
3" (76.2 mm) |
| Thickness |
1/2" (12.7 mm) |
| Center Hole |
1/4" (6.35 mm) |
| Pull Force |
Approximately 165 lbs* |
| Material |
NdFeB (Neodymium-Iron-Boron) |
| Coating |
Nickel-Copper-Nickel (Ni-Cu-Ni) Triple Layer |
| Magnetization |
Through Thickness (Axially Magnetized) |
| Br Max |
13,200 Gauss |
| Certification |
ISO Certified |
*Note: Actual pull force may vary depending on the application, contact surface, steel thickness, air gap, and mounting method. Magnets with a center hole may exhibit different holding characteristics than solid disc magnets. Testing in your specific application is recommended.
Quick Answers
| Question |
Answer |
| How strong is this magnet? |
Approximately 165 lbs of pull force under ideal conditions. |
| What is this magnet made of? |
NdFeB (Neodymium-Iron-Boron) rare earth material. |
| Is this stronger than N35 magnets? |
Yes. N42 delivers greater magnetic strength than N40, N38, and N35 magnets of the same size. |
| Can it be used outdoors? |
Yes, but additional sealing is recommended for long-term outdoor or marine environments. |
| What is it commonly used for? |
Shaft mounting, rotary assemblies, industrial machinery, magnetic fixtures, engineering projects, robotics, and custom equipment. |
Product Overview
These 3" x 1/2" N42 Neodymium Disc Magnets with a 1/4" Center Hole combine exceptional magnetic strength with the convenience of a precision-machined through hole for mounting or shaft applications. The 3-inch diameter provides a large magnetic contact area, while the 1/2-inch thickness generates approximately 165 pounds of pull force under ideal conditions. The 1/4-inch center hole allows the magnet to be integrated into rotating assemblies, custom fixtures, mechanical systems, and specialized equipment.
Manufactured from premium N42 grade NdFeB (Neodymium-Iron-Boron), these magnets deliver significantly greater magnetic performance than N40, N38, and N35 grades. They are ideal for industrial tooling, magnetic couplings, engineering prototypes, automation systems, scientific equipment, and custom machinery where both mounting flexibility and strong magnetic performance are required.
Each magnet features a durable Nickel-Copper-Nickel (Ni-Cu-Ni) triple-layer coating, providing outstanding resistance to corrosion, scratches, and chipping while maintaining a smooth, polished finish. Manufactured in ISO-certified facilities, these magnets provide consistent quality and dependable long-term performance.
What Is a Neodymium Disc Magnet with a Center Hole?
A neodymium disc magnet with a center hole is a permanent NdFeB (Neodymium-Iron-Boron) magnet featuring a precision-machined hole through its center for mounting, alignment, or shaft applications. The center hole allows the magnet to be incorporated into rotating mechanisms, mechanical assemblies, and custom fixtures while maintaining exceptional magnetic strength.
This magnet is magnetized through its 1/2-inch thickness (axially magnetized), placing the north and south poles on the two flat circular faces. This orientation maximizes holding force while allowing the center hole to be used for secure mechanical integration.
Neodymium magnets are also commonly known as Neo magnets, NdFeB magnets, NIB magnets, or super magnets.
How Strong Is This Magnet?
This 3" x 1/2" N42 disc magnet with a 1/4-inch center hole delivers approximately 165 pounds of pull force under ideal laboratory conditions using a thick, clean steel surface.
Actual holding force depends on several factors, including:
- Surface material
- Steel thickness
- Contact area
- Air gap
- Mounting method
- Environmental conditions
Because of the center hole, the contact area is reduced compared to a solid disc magnet. Testing is recommended to verify performance in your specific application.
Technical Specifications
| Specification |
Value |
| Magnet Type |
Neodymium Rare Earth Disc Magnet |
| Grade |
N42 |
| Shape |
Disc with Center Hole |
| Diameter |
3" (76.2 mm) |
| Thickness |
1/2" (12.7 mm) |
| Center Hole |
1/4" (6.35 mm) |
| Pull Force |
Approximately 165 lbs* |
| Material |
NdFeB (Neodymium-Iron-Boron) |
| Coating |
Nickel-Copper-Nickel Triple Layer |
| Magnetization |
Through Thickness (Axially Magnetized) |
| Br Max |
13,200 Gauss |
| Certification |
ISO Certified |
Magnet Grade Comparison
| Grade |
Relative Strength |
Typical Applications |
| N35 |
Standard |
General purpose |
| N38 |
Moderate |
Consumer products |
| N40 |
High |
Industrial |
| N42 |
Higher |
Engineering |
| N52 |
Maximum |
High-performance |
Disc Magnet Size Comparison
| Size |
Typical Use |
| Small |
Crafts & sensors |
| Medium |
General holding |
| Large (3" × 1/2") |
Industrial fixtures, rotary assemblies, machinery, and engineering systems |
Applications by Industry
| Industry |
Common Uses |
| Manufacturing |
Fixtures & jigs |
| Robotics |
Rotary mechanisms & positioning |
| Industrial |
Machinery, tooling & magnetic couplings |
| Engineering |
Prototype development & custom assemblies |
| Scientific |
Laboratory equipment |
| DIY |
Custom mechanical and fabrication projects |
Common Questions About This Magnet
What is the pull force?
This magnet provides approximately 165 pounds of pull force under ideal testing conditions.
What is the purpose of the center hole?
The 1/4-inch center hole allows the magnet to be mounted on shafts, bolts, or custom hardware for rotating assemblies, mechanical fixtures, and specialized equipment.
Is N42 stronger than N35 magnets?
Yes. N42 delivers significantly greater magnetic strength and holding power than N35 magnets of the same dimensions.
Can it rust?
The Nickel-Copper-Nickel triple-layer coating provides excellent corrosion resistance. If the coating becomes damaged and moisture reaches the magnet, corrosion may eventually occur.
Can it be used outdoors?
Yes. However, additional sealing is recommended for prolonged outdoor exposure or marine environments.
What direction is it magnetized?
This magnet is magnetized through its 1/2-inch thickness (axially magnetized), with the north and south poles located on the two flat circular faces.
Do you offer bulk discounts?
Yes. Contact Super Magnet Store for wholesale pricing and volume discounts on commercial, industrial, OEM, educational, and reseller orders.
Why Buy From Super Magnet Store?
- Premium NdFeB rare earth magnets
- ISO-certified quality
- High-performance N42 magnetic grade
- Precision-machined 1/4-inch center hole
- Durable Nickel-Copper-Nickel triple-layer coating
- Consistent magnetic performance
- Excellent corrosion resistance
- Precision manufacturing
- Competitive pricing
- Bulk discounts available
- Fast shipping
- Trusted by manufacturers, engineers, educators, researchers, and DIY professionals worldwide
