One hundred rare-earth magnets in the two most useful hobby sizes: 80 at 3x1mm and 20 at 5x1mm, all high-grade N52 neodymium — the strongest common grade. Model railroaders use them everywhere: swappable open-car loads, removable structure roofs, hidden hatch and shell fasteners, magnetic uncoupling projects, and scenery pieces that lift off for cleaning.
Drill the pockets with the Pin Vise Drill and bed them in Green Stuff for a permanent, invisible install.
How do I keep polarity straight?
Stack the magnets, mark the top face of the whole stack with a marker, and always glue marked-face-out. Mixed polarity is the #1 magnetizing mistake.
What drill size do I need?
A 3mm or 5mm bit matching the magnet — drill a shallow pocket, drop in a dab of CA glue or Green Stuff, and press the magnet flush.
Will they affect DCC decoders or motors?
At these sizes, no practical effect — just keep them away from open-frame motor magnets and magnetic uncoupler ramps you did not intend to trigger.
