Engineered with an aspect ratio where length equals or exceeds diameter (L ≥ D), our sintered neodymium cylinder and rod magnets (NdFeB) project intense magnetic flux lines significantly farther through air gaps than flat disc magnets. Magnetized axially through their length with poles on the opposing flat circular ends, these high-energy rare-earth rods provide deep reaching power for reed switches, Hall-effect sensors, deep blind-hole insertions, and industrial separation assemblies.
Related Neodymium Geometries & Mounting Options:
Extended magnetic length projects flux further outward across air gaps than flat discs.
Ideal for press-fitting into drilled cylinders, aluminum tubes, plastic housings, or wood dowels.
Sintered NdFeB alloys offering surface fields up to 14,000+ Gauss for maximum trigger sensitivity.
Electrolytic nickel-copper-nickel protective barrier provides durability and corrosion resistance.
In magnetic circuit design, the aspect ratio of a permanent magnet dictates how its flux density is distributed into the surrounding air. When a cylindrical magnet has a length equal to or greater than its diameter (L ≥ D), its working point on the demagnetization curve (permeance coefficient, Pc) rises significantly. This increased magnetic length reduces self-demagnetization and allows the magnetic field to reach deeper into surrounding space than a thin disc magnet.
| Attribute | Cylinder / Rod Magnet | Disc Magnet |
|---|---|---|
| Aspect Ratio Definition | Length / Height ≥ Diameter (L ≥ D) | Thickness < Diameter (T < D) |
| Air-Gap Flux Projection | Deep projected reach; maintains high field strength at distance. | Flatter profile; field drops off quickly as distance increases. |
| Direct Contact Pull Force | High, but gains plateau once length exceeds diameter significantly. | Optimized for close flush-contact holding on flat steel plates. |
| Typical Mounting Method | Press-fit into drilled holes, tubular sleeves, or channel tracks. | Surface bonding, shallow mortises, or countersunk screws. |
All products in this category are standard axially magnetized, meaning the magnetic poles are located on the flat circular ends. If you require magnets magnetized across the curved diameter for rotary encoders or stirring bars, please visit our Diametric Neodymium Magnets category.
No. When in direct contact with a steel plate, doubling the length provides diminishing returns once the length exceeds the diameter. However, doubling the length dramatically increases the reach of the magnetic field at a distance through air gaps.
Standard grades (N35 to N52) operate reliably up to 80°C (176°F). For hot operating environments such as motors or heated tooling fixtures, CMS Magnetics also supplies high-temperature grades: M (100°C), H (120°C), and SH (150°C).
Yes. Stacking two or more axial cylinder magnets end-to-end combines their magnetic lengths, behaving essentially as a single longer rod magnet with deeper flux projection.