1/4 x 1/8 Inch Neodymium Rare Earth Diametric Disc Magnet N42 D42DIA

D42DIA Specifications

• Dimensions: This shows the name of each dimension and how it is measured in the image.
• Magnetization Direction: The direction through which the magnet is magnetized. See our Magnetization Directions page for more details.
  Diametrically Magnetized
• Size: Size is the physical dimensions of the product using the standard unit of measure inches.
  0.25 x 0.125 Inch ( Diameter x Thickness )
• Metric Size: Metric size is the physical dimensions of the product in metric millimeters.
  6.35 x 3.17 mm ( Diameter x Thickness )
• Pull Force 1: Pull force case 1 represents a magnet attracting to a thick steel plate. Learn more about Magnet Pull Force Case 1.
  1.32 lb (0.6 kg)
• Pull Force 2: Pull force case 2 represents a magnet attracting to a thick steel plate on both sides. Learn more about Magnet Pull Force Case 2.
  1.8 lb (0.82 kg)
• Grade:

  Grade N

  Min: -238°F (-150°C) Max: 176°F (80°C)

  Hover over grades for temp info:

  • N
  • NM
  • NH
  • NSH
  • NUH
  • NEH
  • NAH
  N42
• Max Operating Temp: Maximum operating temperature, also known as maximum service temperature, is the temperature at which the magnet may be exposed to continuously with no significant long-range instability or structural changes. Learn more in our Temperature and Neodymium Magnets article.
  176°F (80°C)
• Surface Field: Surface field is the magnetic field strength at the surface of the magnet as measured by a Gauss meter. Our Surface Field Table is a comprehensive table of the surface field for all of our stock magnets. Learn about magnet surface field calculations in our Surface Fields 101 article.
  6898 Gauss
• Material: This lists the name of the material each product is composed of.
  Neodymium (NdFeb)
• BH Max: BH max is the Maximum Energy Product at the point on the B/H Curve that has the most strength, expressed in MGOe (MegaGaussOersteds). When describing the grade of a neodymium magnet, this number is commonly referred to as the "N" number, as in Grade N52 magnets. Learn more about Bh max in our glossary.
  42 MGOe
• Tolerances: Dimensional tolerance specifies the allowed leeway for variations in manufacturing.
  ±0.004 in (.1mm)
• Coating: Most neodymium magnets are plated or coated in order to protect the magnet material from corrosion. Check out our Custom Magnets for unplated magnets and other coatings not stocked for this size magnet. Learn more about all available platings and coating in our What Magnet Coating Should I Use? article.
  Nickel-Copper-Nickel (Ni-Cu-Ni)
• Weight: This is the weight of a single magnet in ounces and grams.
  0.0266 oz (0.75 g)
• Br Max: Br max is also called "Residual Flux Density" and is when the magnetic induction remaining in a saturated magnetic material after the magnetizing field has been removed. This is the point at which the hysteresis loop crosses the B axis at zero magnetizing force, and represents the maximum flux output from the given magnet material. By definition, this point occurs at zero air gap, and therefore cannot be seen in practical use of magnet materials. Learn more about Br max in our glossary.
  13,200 Gauss
• Color: The color of the coating or plating on the product.
  Silver

These discs are "diametrically magnetized," which means that the poles are located on opposite sides of the circular shape, not in the center of the circular flat surfaces like most disc magnets. The magnets will tend to want to line up side-to-side rather than stack on their flat surfaces. The unusual magnetization makes them an interesting disc to experiment with.

These discs are often used with Hall Effect switches and sensors.

This size is also available axially magnetized in grade N52 with silver nickel plating as part number D42-N52, in grade N42 with silver nickel plating as part number D42, in grade N42 with black epoxy coating as part number D42E, and in grade N52 with black nickel plating as part number D42B-N52.