Step 2: Organize magnets

Organize the magnets by polarity before you glue them in. Every magnet must face the right way:

• Keys: the south pole faces out of the key.
• Clusters: the north pole faces out of the cluster.

If you don’t have a reference to tell the poles apart, use a compass. Hold the magnet in your fingers or in something non-metal, so nothing else affects the reading.

There are several good ways to stage the magnets.

Magnet stages

The magnet stages hold magnets in rows on their top surface, all with the same pole up.

1. Glue magnets into the back of the stage, all with the same polarity. This turns the stage into a magnetic base.
2. On the Key magnet stage, the working surface must hold magnets with the south pole up.
3. On the Cluster magnet stage, the working surface must hold magnets with the north pole up.
4. Drop as many magnets as you need onto the stage.
5. Pick them up one at a time with a small flat screwdriver, and press each into a key or cluster. They always come off the stage with the right pole out.

For a single build, print the compact 4x3 stages, or fill one row or column of the larger 8x8 stage.

Magnet dispenser

The magnet dispenser holds a stack of magnets and drops them one at a time onto a stage. Print it at 0.3 mm layer height with no supports.

Alternative: a MagSafe phone

You can also stage magnet stacks on the MagSafe ring of an iPhone 12 or newer. This works even with a MagSafe case on.

• The stack farther from the center has the south pole up. Use it for keys.
• The stack closer to the center has the north pole up. Use it for clusters.

Reference: page 152 of Apple’s Accessory Design Guidelines for Apple Devices.

To install a magnet, pick one up from the correct stack with a magnetic tool, put a drop of glue in the magnet hole, and insert the magnet.