We supply precision-ground Flat Ring Neodymium Magnets (also known as Magnetic Washers or “Donut” Magnets). As shown in our product example (22 mm OD×1.5 mm T), these components feature a low-profile, flat geometry with a central clearance hole. They can integrate seamlessly with standard hardware. And function as magnetic spacers or locking washers in assemblies where vertical space is restricted. These Straight-Hole Rings are for “Pass-Through” applications. They allow a bolt, shaft, or axle to pass freely through the center. Meanwhile, the magnet provides a clamping force on the surrounding flat face. Why use a Magnetic Washer? 1. “Zero-Profile” Fastening: The Application: – Adding magnetism to a bolt or screw. The Function: – Slide this magnet onto a non-magnetic screw (like a washer). The Benefit: – It instantly turns a standard screw into a magnetic catch or latch. – But without requiring complex housing or glue. – The 1.5mm thickness is designed to fit under standard screw heads, but not interfering with the thread engagement. 2. Shaft Collars & Spacers: The Function: – The ring fits over a rotating shaft. The Benefit: – It can act as a magnetic spacer to repel other components (magnetic bearings) or trigger a stationary sensor as the shaft rotates. Expert Warning: Fragility (The “Snap” Risk) A 22 mm ring that is only 1.5 mm thick is extremely fragile. Handling Thin Rings: Please note that Sintered Neodymium is a brittle ceramic. A ring with this High Diameter-to-Thickness Ratio (22:1.5) is sensitive to bending forces. Installation: – It must be installed against a perfectly flat surface. – If you screw it down onto an uneven surface, the torque will crack the ring instantly. Torque: – Do not over-tighten the screw passing through the hole. – The washer is designed for clamping magnetic force, not structural compression force. Magnetization Orientation Axial (Through Thickness): – The standard. – One flat face is North, the other is South. – This is used for clamping/holding. Diametric: – Magnetized across the diameter. Use: – If the ring is placed on a shaft to trigger a Hall Effect rotational sensor. Surface Coatings Nickel (Ni-Cu-Ni): – As shown. – Provides a clean, bright finish. Zinc (Zn): – Good for industrial washers. Parylene: – Recommended if the washer is used in a fluid environment (e.g., inside a valve). Rubber Coated: – We can coat larger rings in rubber to provide friction. – And prevent the magnet from sliding down a vertical surface. Applications Magnetic Fasteners: Holding signs or covers where a screw is present. Suspension Systems: Repelling magnet rings on a shaft (Magnetic Spring). Sensors: “Floating” ring magnets for liquid level sensors. Crafts & Closures: Sew-in magnets for handbags (the hole allows for stitching). Ordering Guide: What We Need To quote this, we need 3 dimensions: 1). OD: Outer Diameter (22 mm). 2). ID: Inner Diameter (Hole Size). – Tip: Tell us “Fits M5 screw” and we will calculate the clearance. 3). Thickness: (1.5 mm). 4). Quantity: (Thin rings are produced in large batches).