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Organic Chemistry Molecular Model Sets, Permanent Neodymium Rare Earth Magnets, Magnifying Glasses, Test Strips, Lab Supplies, Tuning Forks

Neodymium Block Magnets
Field Strengths & Holding Force

Block magnet field strengths have been calculated using finite element analysis at the surface and 4 places above the central point and are estimated to be within 10% of actual. For surface measurements, these values are more accurate than a magnetometer since such devices have an airgap of at least 0.1mm between the magnet and sensor.

The 0mm measurement is a maximum theoretical value that assumes there is no nickel coating.

The holding forces are also theoretical maximums based on optimum permeability, thickness, area of the metal attached to and no nickel or other coating. The attractive/repulsive force of 2 identical magnets is double this value.
  • N42 grade: ~13,000 gauss (1.3T)
  • nickel-copper-nickel coated
  • size tolerance for dimensions <10mm: +/- 0.05mm
  • size tolerance for dimensions >10mm: +/- 0.1mm
  • size tolerance for dimensions >50mm: +/- 0.2mm
  • magnet strength variance piece to piece: <8%
  • 80C maximum operating temperature
  • axis of magnetization is perpendicular to page
Click to see

Scientific notation explained:
1.15E+03=1150      1.15E+02=115     1.15E+01=11.5

1.15E+00=1.15      1.15E-01=0.115     1.15E-02=0.0115

American & Canadian Coin Sizes: Smallest to Largest
Dime: ~18x1.2mm; Penny: ~19x1.45mm; Nickel: ~21x1.75mm; Quarter: ~24x1.6mm.
NdFeB rectangular block magnets
Field Strengths (in gauss) at 5 Distances (in mm); Holding Force in 3 Units
Size (mm)00.1110100lbsgmsN
4x2x13.72E+033.48E+031.53E+031.40E+012.00E-020.41992
5x2.5x13.19E+033.04E+031.62E+032.13E+013.00E-020.62512
10x2.5x2.54.87E+034.60E+032.49E+037.79E+011.30E-012.08869
10x5x2.53.72E+033.63E+032.72E+031.50E+022.50E-012.8125612
10x5x55.25E+035.1E+033.76E+032.38E+024.90E-015.5251125
12.5x2.5x2.54.80E+034.53E+032.45E+038.94E+011.60E-012.299110
12.5x5x2.53.59E+033.50E+032.64E+031.73E+023.10E-013.1140514
12.5x5x55.10E+034.96E+033.69E+032.76E+026.10E-016.2280928
20x10x56.47E+036.29E+034.69E+033.99E+021.6E-0011.1502449
25x2.5x2.54.69E+034.42E+032.36E+031.12E+023.10E-013.1140314
25x5x2.53.38E+033.29E+032.47E+032.16E+026.20E-014.4198519
25x5x54.80E+034.66E+033.48E+033.58E+021.20E+008.8397139
25x10x2.52.11E+032.09E+031.89E+033.82E+021.24E+006.2280728
25x10x53.59E+033.55E+033.12E+036.42E+022.40E+0012.4561555
25x12.5x2.51.79E+031.78E+031.66E+034.41E+021.55E+006.9314131
25x12.5x53.91E+033.16E+032.88E+037.48E+023.00E+0013.9628262
50x5x2.53.32E+033.24E+032.42E+032.14E+021.19E+006.2280728

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