The 12.5x25mm size rare earth Nd rod is ideal for demonstrating Eddy current braking. The 12.5mm size is just slightly smaller than the ID of a 1/2" copper tube & the 25mm length has the most surface area. Works with 1/2" diameter copper or aluminum pipe.
The Mark II Magnaprobe is an excellent tool for detecting magnetic fields & is must for any college or high school electricity & magnetism lab. See it in action below in our eddy current-drop tower braking simulation or read our blog Eddy Current Copper Tube Drop Tower Brake Test.
Even more impressive is the ultrasensitive Mark I Magnaprobe which responds to magnetic fields as weak as 0.3 gauss. A must if your cyclotron or particle collider is slightly off. In this instance, it was able to detect the eddy current in the simulation below at a distance of over 1m (3.3 feet)!
Want to spend less and really get your best bang for the buck? Here are reviews some customers did on our Google pages.
Ron Bennett: Fantastic support and product. Beats Amazon price with real customer service. After online order was placed, they called and and asked if I had any questions and gave clear instructions on pickup process. Order was ready and in stock and the product was of the highest quality and exactly...
Tracy Myerson: Super fast shipping, excellent prices, and great quality product! I purchased N42 Neodymium magnets, they are the real deal. I had previously bought magnets on Amazon that were advertised as N52, they were just another cheap Chinese fake. These folks sell authentic, high quality....
Ian Kelly: I've dealt with Indigo Instruments for years now. They have always been personable and very knowledgeable. Most recently I sent them a hand-drawn sketch of my interpretation of something I saw on YouTube and wanted recommendations....I couldn't be happier...
Specifications
Field Strength (Gauss) & Pull Force in Pounds & Kilograms at 5 Distances Above Magnet
SKU: 44204-25 Size: 12.5 × 25mm
Distance (mm):
0
0.1
1
10
100
Gauss
6402.9
6298.9
5374.5
900.4
4.6
Lb
16.06
15.54
11.32
0.32
0.00
Kg
7.30
7.06
5.14
0.14
0.00
Magnet Documentation
Drawing
Compliance
MSDS
ROHS
Graph
Specifications for Fully Sintered/Pressed Neodymium Magnets, N42 Grade
RemanentFlux Density (Br)
13,000G; 1300mT
Coercivity (bHc)
12.0 Oe; 955 A/m
Intrinsic Coercivity (jHc)
17.0 Oe; 1353 A/m
Max.Energy Product (BHMax)
42 MGO; 334 kJ/m3
Curie Temperature (Tc)
310oC
Working Temperature (Tw)
80oC
Temp.Coefficient (αB)r
-0.12%/Co
Tolerances - Sintered Rare Earth Magnets
Dimensions
Tolerances
Size:
Unfinished Surfaces:
Dimensions perpendicular to pressing (die formed)
Inches
mm
Inches
mm
0 to 0.125
0 to 3
+/- 0.006
+/- 0.15
0.126 to 0.625
3 to 16
+/- 0.012
+/- 0.30
0.626 to 0.875
16 to 22
+/- 0.018
+/- 0.45
0.876 and Up
22 and Up
+/- 2.5%
+/- 2.5%
American (Imperial)/Metric Conversion Table
Inch
Decimal
mm
Rounded
1/32"
0.031
0.8
1
3/32"
0.094
2.4
2.5
5/32"
0.156
4.0
4
1/16"
0.063
1.6
1.5
3/16"
0.188
4.8
5
2/10"
0.200
5.1
5
1/8"
0.125
3.2
3.75
1/4"
0.250
6.4
7.5
5/16"
0.313
7.9
7.5
3/8"
0.375
9.5
10
13/32"
0.406
10.3
10
1/2"
0.500
12.7
12.5
9/16"
0.563
14.3
15
5/8"
0.625
15.9
15
11/16"
0.688
17.5
17.5
3/4"
0.750
19.1
20
13/16"
0.813
20.6
20
7/8"
0.875
22.2
22.5
15/16"
0.938
23.8
25
See what these customers had to say (click on name for full review):
Tracy Myerson: ...purchased N42 Neodymium magnets, they are the real deal...had previously bought magnets on Amazon that were advertised as N52, they were just another cheap Chinese fake....
Ron Bennett: Fantastic support and product. Beats Amazon price with real customer service...product was of the highest quality and exactly as described
Peter Maran: Their Neodymium magnets are superb in quality and price; ...tools, magnifiers, tweezers, and so on, all quality made...
