Veritas Metric Tapered Snug-Plug Cutters

Keep softwood to 600 rpm maximum and hardwood to 350 rpm maximum, and let the bit cool between batches of plugs, since results vary with material hardness and feed rate.

Yes, hone the face of each tooth with a thin flat file, a sharpening stone or 320x sandpaper glued to hardboard, keeping the factory rake angle. If the tips dull after prolonged use, file the top bevel at the original angle and keep the tooth height even.

Snap it off with a screwdriver, or cut it free with a bandsaw if you need a cleaner break at the surface.

Put a bit of glue in the hole, then tap in a plug with the grain lined up until you feel resistance. Let the glue dry, then trim any remaining projection flush with a chisel, saw or plane.