We supply custom stadium-shaped Neodymium magnets.
Also called racetrack or obround magnets.
They are rectangular bodies with full-radius semicircular ends.
These are engineered to fit CNC-milled slots without modification.
When a CNC mill or router cuts a rectangular slot, it leaves rounded ends where the bit starts and stops.
Stadium magnets match this geometry exactly.
They drop directly into milled recesses for flush mounting.
Standard rectangular magnets require slot modification or leave gaps.
Available in custom sizes for your specific slot dimensions.
The “Slot Fit” Advantage
The Perfect Drop-In Solution:
If you are machining a housing using a standard end-mill or router bit, cutting a square pocket requires complex extra steps (corner chiseling).
The Solution: Cut a simple linear slot.
Our Magnet:
– Fits the slot perfectly.
– The semicircular ends of the magnet match the curvature left by the cutting tool.
The Benefit:
– Reduces machining time and eliminates air gaps at the ends of the magnet.
– This maximizes holding force per square millimeter.
Technical Geometry: Defining the Shape
Let us clarify the math so there is no confusion with “Ovals” (which are egg-shaped).
To ensure we supply the correct shape, we define this as a “Full Radius” profile:
– Parallel Sides: The long sides are perfectly straight and parallel.
– Round Ends: The short ends are perfect semicircles.
– The Formula: The Corner Radius (R) is exactly half of the Width (w).
Example: If the magnet is 10mm wide, the radius on the ends is R5mm.
Production & Tolerances
Since these shapes cannot be cut with standard block slicers, we use advanced profiling methods to ensure the curve is smooth and continuous.
– Material Grade: N35 – N52 (Standard), High Temp Series (UH/EH) for motors
– Profile Tolerance: ±0.05mm (We ensure the “straight-to-curve” transition is seamless)
– Dimensions: Custom Length (L) & Width (W) from small sensor sizes (4mm) to large industrial blocks (100mm+)
– Thickness (T): 1mm – 50mm
Magnetization Orientation
Through Thickness (Axial):
– The standard orientation.
– The large flat faces (the stadium shape) are the North and South poles. Ideal for recessed mounting.
Diametric (Lateral):
– Magnetized across the width.
– Used in specialized rotational sensors or flow meters.
Surface Coatings
Ni-Cu-Ni (Nickel):
– The standard durable finish.
– The rounded ends allow for excellent plating coverage with no sharp edge buildup.
Epoxy (Black):
– Highly recommended if the magnet is being glued into a milled slot.
– Epoxy offers superior adhesion to industrial glues.
Zinc (Zn):
– A cost-effective option for concealed parts.
Applications
Recessed Closures: Cabinetry and furniture where slots are routed into wood.
Molded Inserts: Used in plastic injection molding (the lack of sharp corners reduces stress on the mold and the plastic part).
Liquid Level Sensors: The smooth, hydrodynamic shape allows it to slide easily inside tubes or liquid floats without catching.
Generators: “Racetrack” coil magnets used in specific stator designs.
Ordering Guide: How to Specify
To quote this shape accurately, please provide:
– Length (L): The total length from tip to tip.
– Width (W): The width of the straight section.
– Thickness (T): The height.
Radius Confirmation:
– Just specify “Full Radius” or “Stadium Shape”
– We will automatically calculate that R = W/2)
