MGT cylinder magnet vs other types of magnets: selection guide for makers and engineers

Overview: what is an MGT cylinder magnet and why compare types

MGT cylinder magnets (magnetised through the thickness or along the cylinder axis) are compact cylindrical permanent magnets commonly used in sensors, mounting fixtures, and small actuators. Comparing MGT cylinders with disc, ring, and block magnets helps makers, students and technicians choose the right geometry, field orientation and holding force for their project. This guide explains construction, magnetic orientation, common materials, and practical selection criteria with South African sourcing notes.

Common magnet materials and properties

Most small permanent magnets you’ll encounter are ferrite (ceramic), alnico, samarium-cobalt (SmCo) or neodymium (NdFeB). Neodymium offers the highest energy product for compact parts like MGT cylinders but is more brittle and sensitive to corrosion unless coated. Ferrite is low cost and corrosion resistant but much weaker. For typical maker and student projects in South Africa, NdFeB is the dominant choice when strong fields or small sizes are required.

Magnet geometries and field orientation

Geometry determines how the field lines distribute and how you mount or interact with the magnet. Key types:

• MGT cylinder (axially magnetised): strong dipole along the cylinder axis; good for sensor triggering and concentrated contact points.
• Disc magnets: flat, radial or axial magnetisation; useful for holding plates or thin assemblies.
• Ring magnets: central hole allows fastener passthrough; can be axially or radially magnetised for motor or speaker uses.
• Block (rectangular) magnets: offer predictable flux across flat faces, used in fixtures and housings.

Quick spec comparison table

Mechanical and safety considerations

Neodymium cylinders can snap to steel or other magnets with surprising force: handle small parts with care, keep them away from credit cards and sensitive electronics. When embedding magnets in 3D-printed parts or enclosures, allow clearance for plating/coating thickness and consider mechanical retention (adhesive or press fit). Communica stocks enclosures, adhesives and 3D printing supplies that suit magnet mounting; explore collections to pair parts: Shop by Category.

Sensor wiring note (Hall sensor example)

When using a cylinder magnet with a Hall effect sensor, you will typically wire a pull-up resistor to the sensor output for open-collector types. Use Ohm’s law to size the resistor: V=IR. For a 5 V supply and desired pull-up current of 1 mA, R = 5 V / 1 mA = 5 kOhm. This keeps power low while ensuring reliable logic levels for microcontrollers commonly used by South African students and makers.

For parts and brands commonly used in sensor projects, see Communica’s stock lists under Shop by Brand and the broader components index at All Products.

Selection criteria: choosing the right magnet for your project

Match the magnet type to the application by considering these factors: holding/pull force, field orientation, size constraints, operating temperature, corrosion protection and how you will mount the magnet. Cylinder magnets (MGT) are excellent where a focused axial pole is needed for repeatable actuation over short air gaps. For distributed holding or low-profile mounting, discs or blocks can be better.

Calculating pull force and safe gaps

Manufacturers provide pull force as a reference measured against a thick steel plate at zero gap. Real world holding force falls off rapidly with gap distance. A rough behavior: doubling the gap can reduce force to a small fraction. For critical loads, test the exact geometry. If you need to estimate magnetic flux or field at a point, finite element tools or manufacturer datasheets are the best source; for quick checks, expect NdFeB cylinders to provide useful forces in the tens to hundreds of grams for small diameters (1-5 mm) and several newtons for larger sizes (6-12 mm), depending on grade.

Practical examples and wiring diagram

Example 1 - Door sensor with MGT cylinder and reed switch:

Magnet (MGT) ----- gap ~3-5 mm ----- Reed switch (on door frame)
Wire reed switch in series with microcontroller input and pull-up resistor

Example 2 - Hall sensor for rotary encoder (cylinder mounted on shaft): use a small MGT cylinder glued to the shaft end with a non-magnetic spacer. Ensure axial orientation alternates if you need polarity detection.

Troubleshooting common issues

• Weak trigger: check magnet orientation and air gap; increase magnet diameter or reduce gap.
• Interference with nearby ferrous parts: add non-magnetic spacers or reposition magnet to reduce unintended attraction.
• Mounting failure in plastic housings: use epoxy rated for bonding metal to plastic or design a press-fit pocket sized to manufacturing tolerances.

Availability, lead times and local considerations in South Africa

Stocking levels for specific magnet sizes and grades can vary. Communica maintains a broad range of components and maker supplies from their Samrand head office and branches; check branch collection and trading hours when you need same-day pickup via Branches & Trading Hours. For education or bulk procurement, request account quotes and VAT invoices to align with tertiary budgets and procurement processes - general company background and services are described on the About Us page.

Accessory bundles and complementary parts

When buying cylinder magnets for prototyping, consider ordering small heatsinks, adhesives, non-magnetic fasteners, and sensor breakout boards together to save iteration time. Browse allied categories and tool supplies in the collections index to assemble a complete kit: Collections.

Sources

• Communica - About Us
• Neodymium magnets - Wikipedia (overview of materials and properties)
• Engineering Toolbox - Magnetics reference (practical guidance)
• Communica - Branches & Trading Hours