If you have a late-model laptop, you’ve probably seen how the chargers magnetically snap into place. In theory, this should be easy to recreate for your own purposes. But why reinvent the wheel when [DarthKaker] has already done the work for you — assuming you only need two conductors.

The 3D-printed shells take the usual round magnets. Obviously, the north pole on one part should point to the south pole on the other part. In addition, if polarity matters, you should also have each housing contain one north-facing and one south-facing magnet so that the connectors will only mate one way.

It appears the project uses wires soldered or spot welded to the magnets. Heating magnets sometimes has bad effects, so we might try something different. For example, you could solder the wires to thin washers affixed to the magnets with epoxy, perhaps. Or use the magnets for alignment and make a different arrangement for the contacts, although that would take a different shell design.

We have talked about magnet soldering for connectors before. Don’t forget that you can build magnets into your prints, too.

Most electromagnetic actuators are rotating motors, or some variation on the theme, like servos. However, it’s possible to do linear actuation with electomagnetics, too. [Adrian Perez] demonstrates this with Linette, his design of a linear actuator that he was inspired to build by the structure of our own muscles.

The design uses a coil of copper wire in a 3D-printed plastic housing, surrounded by a claw full of strong magnets. When the coil is activated, the magnets are pulled towards the coil. When the coil is not energized, the magnets fall away. [Adrian] demonstrates the actuator under the control of an Arduino, which switches power to the coil to move it up and down.

He also notes that the design is similar solenoids and voice coil style actuators, though unlike most his uses discrete magnets rather than a single monolithic magnet. It’s possible to get more capacity out of the Linette design through stacking. You can parallelize the actuators to get more pulling force, with neighboring coils sharing the same magnets. Alternatively, you can stack them in series to get longer stroke lengths.

[Adrian] hasn’t put the design to a practical application yet, but we could see multiple uses for robotics or small machines. We’ve seen some other neat DIY magnetic actuators before, too. Video after the break.

The printing press was first invented in 1440 AD by Johannes Gutenberg. It’s not so relevant to our day to day lives today, but it’s a technology that forever changed the path of human history. Now you can whip one up yourself using this teeny design from the [3DPrintingEnthusiast]!

Don’t expect to be making broadsheets with this thing—it’s a strictly table-top sized unit made on a 3D printer. Still, it does the job! The bed, frame, paper holder, and clamps are all 3D-printed. However, you will need some minor additional supplies to complete the carriage and inkballs.

As for your printing plates, you could go out and source some ancient lead type—or you could just 3D print some instead. The latter is probably easier if you’re living in 2024 like yours truly. Who knows, though. 2028 could be a banner year where printing presses roar back to prominence. Try not to think about the global scale disasters that would make that a reality.

In any case, there’s got to be some kind of irony about 3D-printing a printing press on a 3D printer? Perhaps, perhaps not. Debate it below!