We supply custom Neodymium ring magnets in the 3–10mm outer diameter range. Commonly used for electronics, sensors, and precision assemblies. These small-format rings are used in magnetic locks, sensor standoffs, shaft-mounted components. And other applications requiring precise fitment. The critical specifications are concentricity. That means how centered the inner hole is relative to the outer diameter. And tight dimensional tolerances. Poor concentricity causes binding or wobble when the magnet slides onto a pin or shaft. We control both ID and OD grinding to ensure clean assembly-line fitment. Available in custom dimensions and magnetization directions. The “Sweet Spot” Engineering (Durability vs. Size) Since these aren’t “micro” parts, they are often handled by hand or semi-automated tools. You need to aware the structural limits. Wall Thickness & Mechanical Strength: In the 3mm–10mm range, the structural integrity depends entirely on the Wall Thickness (OD – ID / 2). The “Safe” Ratio: – For manual handling, we recommend a wall thickness of at least 1.0mm. The “Fragile” Zone: – If your design requires a very thin wall (e.g., OD 6mm x ID 5.2mm), the ring becomes extremely fragile. – In these cases, we recommend bonding rather than mechanical clamping to prevent cracking. Press-Fit Warning: – Even at this size, Neodymium is ceramic. – Do not press-fit these rings onto shafts. – Always design for a Slip Fit with adhesive (Loctite/Epoxy). Surface Coatings: Functional & Decorative At this size, magnets are often visible in the final product (e.g., magnetic connectors, latch mechanisms). Ni-Cu-Ni (Nickel): – The standard. – Bright silver finish, durable. Gold (Au): – Highly popular in this size range for Pogo-Pin Connectors and battery charging ports. – Ensure conductivity and corrosion resistance against skin contact. Black Epoxy: – Used for optical sensors where reflection must be minimized. – Or, for discrete “stealth” mounting. Magnetization Orientation Axial: Magnetized through the length. Use: Magnetic spacers, lid closures, suspension systems. Diametric: Magnetized across the diameter. Use: Small motor rotors, rotational sensors, hall-effect triggers. Radial: True radial magnetization is technically difficult in this size range. We generally recommend Diametric as the cost-effective alternative. Applications Drones/UAVs: Propeller mounting and gimbal stabilization motors. Vape & Consumer Tech: Magnetic cartridge snaps and charging docks. Robotics: Joint position sensors. Jewelry/Fashion: Magnetic clasps (often Gold plated). Fasteners: Using the ring as a magnetic “spacer” on a non-magnetic screw. Packaging & Assembly While not as critical as the “Micro” rings, proper packaging saves assembly time. Plastic Tube Packing: – Recommended for IDs < 5mm. – Keeps rings aligned and easy to dispense. Foam Separation: – For larger rings (e.g., OD 10mm), we use foam sheets to separate layers – Make it easy to grab individual pieces without them snapping together. Polarity Marking: – We can spray-mark the North pole (red dot) on rings with OD > 4mm. – This helps your assembly team (not possible on smaller micro-rings). Ordering Guide To get a quick quote, please confirm: 1). Dimensions: OD x ID x Length. 2). Shaft Size: “What diameter pin is this going onto?” (We can advise on the correct ID clearance). 3). Grade: Standard N35 or High-Temp? 4). Coating: Do you need Gold (Conductive) or Nickel (Standard)?