25pcs 12mm x 5mm x Hole 4mm Neodymium Straight Ring Magnet – N52 Grade 

Key Features:

• Dimensions: 12mm Outer Diameter × 5mm Thickness × 4mm Inner Hole Diameter
• Straight Hole Profile: Uniform 4mm cylindrical inner diameter (no countersink) for shaft-mounting, pinning, and bolt-through setups
• Precision Tolerance: ±0.05mm
• Magnet Grade: N52 
• Pull Force: Approx. 8.78 lbs 
• Coating: Nickel-Copper-Nickel (Ni-Cu-Ni) triple-layer plating for superior durability
• Magnetization: Axially magnetized (Poles on the flat circular faces, providing uniform flux distribution)

Material Description:

Our 12mm x 5mm uniform N52 ring magnets are engineered specifically for complex mechanical, automation, and industrial fabrication projects where a non-countersunk through-hole is mandatory. The substantial 5mm thickness provides massive magnetic volume, allowing the deep field to project through non-magnetic finishes or small air gaps. The straight 4mm inner bore allows this magnet to be seamlessly pressed onto steel axles, utilized in magnetic bearings, or held securely via non-magnetic machine bolts and pins. Because both circular faces remain entirely flat, this ring can be stacked back-to-back to compound magnetic force or used in alternating arrays for high-torque magnetic couplings and contactless sensory drive systems.

Handling Advice: DANGER: Industrial-strength ring profiles require careful, controlled installation. Neodymium is inherently brittle like ceramic. While straight cylindrical holes distribute mechanical clamping force much more evenly than countersunk pockets, over-tightening bolts or pins can still crack the core—always hand-tighten with care. These magnets also possess immense snap velocity; never let them free-fly together or snap onto steel tools, as they will shatter violently upon impact.

Warnings and Safety Information:

• Crush Hazard: High risk of serious skin and finger pinches or blood blisters. Handle with industrial focus.
• Brittle Core Warning: Sintered neodymium is fragile. High-impact collisions or dropping onto hard surfaces will fracture the ring wall.
• CHOKING HAZARD: Keep securely stored and out of reach of children and pets.
• Medical Safety: KEEP AWAY from pacemakers and sensitive medical implants at all times.

Applications:

• High-torque magnetic couplings, rotary encoders, and contactless drive linkages for automated manufacturing
• Industrial magnetic bearings, guide rollers, and shaft-mounted rotational assemblies
• Pass-through sensor rings for heavy automation, pneumatic pistons, and Hall-effect electronics
• Secure bolt-through anchoring for custom machinery enclosures, heavy equipment hatches, and guarding panels
• High-vibration shop-tool organization, magnetic separator assemblies, and custom mounting jigs