40x10x5mm Neodymium BAR Magnet

Specifications:

• Material: Neodymium Iron Boron (NdFeB) Rare-Earth
• Magnetic Grade: N40
• Shape: Rectangular Bar / Block
• Dimensions: 40mm (L) x 10mm (W) x 5mm (H)
• Coating: Triple-Layer Ni-Cu-Ni (Nickel-Copper-Nickel)
• Maximum Operating Temperature: 80°C (176°F)

Application

Safe Separation: Never pull magnets straight apart or let them aggressively snap together, as the brittle NdFeB material will chip. Always slide them apart sideways.
Sensor Actuation: If using this magnet with a Hall Effect sensor or Reed Switch, ensure the flat 40x10mm face (where the magnetic poles are located) directly faces the sensor.
Surface Mounting: Use strong adhesives like two-part epoxy or cyanoacrylate. Avoid hot glue, as the heat can degrade the magnet's strength and the bond is often too weak.
Project Evolution

Past Projects: In the past, achieving a strong magnetic hold meant using thick, obtrusive ferrite magnets or bulky mechanical latches that ruined the clean lines of your enclosures.
Feature Upgrade: Upgrading to this ultra-slim 5mm neodymium bar lets you integrate powerful, invisible magnetic snaps into the tightest clearances. It's the ultimate choice for sleek 3D printed puzzle boxes, low-profile tool changers, or embedding inside thin acrylic sheets for magnetic displays.
Effort Level & Minimum Hardware: Beginner. No specialized tools are needed. You can mount these using a dab of CA glue (super glue), two-part epoxy, or simply design a tight-tolerance pocket into your 3D models for a clean press-fit.
Included in the Box:

• 1× 40x10x5mm Neodymium Bar Magnet

Frequently Asked Questions

• What is the magnetic grade of this bar?
  It is manufactured to an industrial N40 grade.
• Where are the north and south poles located?
  It is magnetized through the thickness, meaning the poles are on the two large 40x10mm flat faces.
• Can I drill a hole in this magnet for mounting?
  No. Neodymium is incredibly brittle and drilling will shatter it. The dust produced is also highly flammable.
• Is it safe to solder wires directly to the magnet?
  No. The intense heat of a soldering iron will permanently destroy its magnetic properties.
• What is the maximum operating temperature?
  The maximum recommended operating temperature is 80°C (176°F).
• What happens if it gets hotter than 80°C?
  It will suffer irreversible loss of its magnetic strength.
• Is this magnet waterproof?
  The triple-layer Ni-Cu-Ni plating offers excellent corrosion resistance, but prolonged exposure to water or harsh outdoor environments may eventually cause the iron core to rust.
• Can I use this to trigger a reed switch?
  Yes, it provides a strong and reliable magnetic field perfect for actuating reed switches.
• Will this work with an Arduino Hall Effect sensor module?
  Absolutely. It is an excellent target for Hall Effect sensors in RPM counters or limit switches.
• What is the best way to attach this to my project?
  Cyanoacrylate (super glue), two-part epoxy, or double-sided mounting tape work best.
• Why did my magnet chip when it attached to another?
  Neodymium magnets are very brittle. Allowing them to snap together from a distance can cause them to chip or shatter upon impact.