We supply precision-machined custom Small Rectangular Neodymium Magnets with 2 countersunk holes.
The specific model shown (20mm×10mm×4mm) is a best-seller for compact mounting applications.
Their space is limited but mechanical security is non-negotiable.
Generally, single-hole magnets can spin out of alignment.
But this Double-Hole configuration ensures the magnet remains perfectly parallel to your mounting surface.
Featuring premium Radiused Edges (as seen in the photo), these blocks are designed to be screwed flush onto:
– Non-magnetic surfaces like wood, plastic, or aluminum
– And create a permanent magnetic fixture without the mess of adhesives
Why 2 Holes in a Small Block Magnet?
1. The “Anti-Rotation” Lock:
In a small block (20mm long), a single center screw acts as a pivot.
The Problem:
– Any vibration or impact will cause the magnet to spin.
The Solution:
– The second hole acts as a geometric lock.
– Once both screws are installed, the magnet is rigidly fixed in orientation.
2. Distributed Clamping Force:
The Benefit:
– Use two smaller screws (e.g., M3) instead of one large screw, you distribute the pressure across the ceramic body.
– This reduces the risk of cracking the magnet during installation compared to a single high-torque point.
Installation Advice: The “Thin Wall” Warning
For a 10mm wide magnet with holes, the wall thickness is critical.
Handling Fragility:
At 10mm wide, the “web” (the material between the screw hole and the outer edge) is thin.
Screw Size:
– We typically design these to fit M3 Flat Head Screws.
– Using larger screws risks cracking the side walls.
Torque:
– Do not use power drills.
– Hand-tighten screws only until snug.
– The countersink is the weakest part of the magnet; overtightening will split the block.
Flush Fit:
– Ensure your screw head angle matches the countersink angle (standard 90°).
– Make sure the head sits flush or sub-flush.
Polarity & “Matched Pairs”
Critical for latching applications.
Are you using these for door closures?
If you are using two magnets facing each other (e.g., one on the door, one on the frame), you need Matched Pairs.
– Side A: North Pole on the Countersunk Face.
– Side B: South Pole on the Countersunk Face.
Please specify if you need “Pairs” in your order.
Otherwise, we supply standard polarity.
Surface Coatings
Nickel (Ni-Cu-Ni): (As shown in photo). Durable and shiny, ideal for visible mounting.
Zinc (Zn): Matte finish, good for concealed joinery.
Rubber Coated: Available for larger versions to provide grip.
Applications
3D Printing: Embedded magnets in PLA/PETG enclosures.
Cabinetry: Door catches for small cupboards or jewelry boxes.
Sensor Mounting: Fixing Hall Effect sensors to a machine frame.
Camera Rigs: Small, quick-release mounting points.
Ordering Guide: Critical Data
To quote this item, please provide:
1). Dimensions: Length (20) x Width (10) x Thickness (4).
2). Hole Size: What screw size must it fit? (e.g., M3).
3). Hole Pitch: Distance center-to-center.
4). Quantity: (Pairs or Single Polarity?).
