Magnetic extension for Prusa MK42 heatbed (used in MK2/MK2S)

I wanted to add magnets to my MK2S, which has the MK42 heatbed. The assembly manual warns that the thread in the headbed is very delicate, so I didn't want to unscrew it to dremel out slots for the magnets. So instead I made some holders for the magnets that clamp around the posts that the heatbed is attached to.

You will need:

• PETG or similar filament, as PLA will likely melt
• 20 magnets (25x6x2mm). I recommend getting neodymium magnets with an SH rating, like these. Regular neodymium magnets lose their magnetism at 80C, this bed can go to 120C, and SH rated magnets to 150C.
• 4 tiewraps, 3x100mm (should be about 1mm thick)
• Glue to hold the magnets in place. Without some glue, the magnets will flip when you put their neighbors in.
• One of the steel sheets from Prusa. 

Only the Back piece needs supports, everything else should be printed without.

Once installed you should run a Z calibration, and the PINDA should have no trouble detecting the steel sheet. It will actually end up a little further away than it needs to be, so run a first layer calibration. Regular heatbed was at -0.450 for me, powder coated satin sheet needed something like -1.400, but your mileage may vary.

Thanks to https://github.com/prusa3d/Heatbed_MK52_magnetic and https://github.com/prusa3d/Original-Prusa-i3/tree/MK2S/Heatbed MK42 for all the info that was needed to design this.

Included Fusion 360 export for those wanting to remix.