Neodymium magnets blocks with hole
We also offer magnets with holes for countersunk screws. We recommend purchasing magnets with holes, as drilling into magnets is not recommended; they are fragile and likely to crack.
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1Choose the footprint, because the height is fixed
Every block in this category is 4 mm high and differs only in its footprint: 15 x 15, 20 x 20, 40 x 20, 40 x 40 and 60 x 20 mm. The pull force follows the contact area, so the choice comes down to how much flat surface you have available.
The long narrow versions, 40 x 20 and 60 x 20, suit door edges, frames and profiles where a square magnet would not fit. The square ones give the most force per screw.
2Use a countersunk screw and nothing else
The hole is countersunk on the front face so that the head of a countersunk screw finishes flush with the magnet. A pan or cap head stands proud, lifts the magnet off the steel it should be holding and wedges against the brittle edge while you tighten it.
Tighten by hand until the magnet seats and then stop. For assemblies that vibrate, use a thread locking compound rather than more torque.
3Match the pull force to the job with a reserve
These blocks cover roughly 2 to 50 kg depending on the size. The figure is measured in direct contact with a thick, flat, clean steel plate, so plan for 2 to 3 times the weight you actually need to hold.
With a footprint this large, the flatness of the mounting surface matters as much as the rating: a block that only touches along two corners delivers a fraction of its force and is much more likely to crack.
4Never drill the hole yourself
The hole is machined into the blank before the magnet is magnetised and plated. Drilling a finished magnet cracks it, damages the coating so corrosion starts at the break, and the heat generated demagnetises the material permanently. If none of the five stocked sizes fits, ask us for a custom piece instead of modifying a standard one.
5Check the temperature and the environment
All blocks in this category are standard N grade for use up to roughly 80 °C, with nickel plating designed for dry interiors. For a warmer or damp location, look at the grades and coatings in the wider neodymium range and ask us before ordering.
Tip: With a screwed block, the screw takes the shear load and the magnet only has to supply the pull. That makes this design far more reliable than a glued block on a door or a hatch, where side forces peel an adhesive joint apart over time.
Related categories to the Blocks with hole category
- Cylinders with hole
- Magnets with holes
- Magnetic fastening kits
- Counterpart to magnet with hole
- Neodymium block magnets
- Block magnets by pull force
- Pull force 2 to 5 kg
- Pull force 5 to 15 kg
- Pull force 15 to 50 kg
- Height up to 5 mm
- Self-adhesive block magnets
- Flat block magnets
- Neodymium ring magnets
- Door magnets
- All neodymium magnets
Frequently asked questions about block magnets with a hole
Five footprints, all 4 mm high: 15 x 15, 20 x 20, 40 x 20, 40 x 40 and 60 x 20 mm. Because the height is the same across the range, the pull force follows the contact area, from roughly 2 kg for the smallest square up to the 15 to 50 kg band for the largest pieces.
A countersunk head screw. The hole is countersunk on the front face specifically so the head finishes flush with the magnet and does not lift it away from the steel. A pan or cap head would both reduce the hold and wedge against the brittle edge of the magnet as it is tightened.
Because of the direction of the load. Adhesive is strong in tension but weak in shear, so a glued magnet on a door or a hatch gradually peels as the panel is pulled sideways. With a screw, the fastener carries the shear load and the magnet only has to supply the pull, which is what it is good at.
No. The hole is machined into the blank before magnetisation and plating. Drilling a finished magnet cracks the brittle material, destroys the corrosion protection and the heat from the drill causes a permanent loss of force. If none of the stocked sizes fits your design, a custom piece can be quoted on enquiry.
All of them are standard N grade rated for use up to roughly 80 °C, with nickel plating intended for dry interiors. For warmer locations or damp and outdoor environments, the wider neodymium range offers higher grades and epoxy or rubberised coatings; contact us and we will point you to a suitable equivalent.
A screw fixing is the most reliable way to mount a magnet, and the only safe way to get a hole into neodymium is to have it machined into the blank before magnetisation and plating. These blocks come in five footprints, from 15 x 15 to 60 x 20 mm, all 4 mm high, with a countersunk hole and a pull force from roughly 2 kg up to the 15 to 50 kg band. Matching counterparts and complete fastening kits are in stock alongside them.
