I want to make a knife bar out of rare earth magnets to hold my kitchen
knives. If I hold the surface of the knives off just a tad, can I avoid the
scratching that would be produced with the knives touching metal to metal?
Or will there be enough magnetic attraction if I use thicker magnets to suck
them up against a oak or plastic substrate that would be sufficient to keep
them in place, and a few thousandths of airspace between?

Or lastly, to apply a thin plastic face onto the magnet so that it never
touches metal to metal?

Steve