Use a 1/4" metal drill bit to drill the holes in the lids and a 1/16" bit to drill 6 small holes around the lid to allow heat to escape from the jar. (I eyeballed the air holes, as no one would see them.) Next, insert the metal nipple through the hole leaving equal lengths on each side of the lid. Be careful, as the lids are very light gauge and razor sharp shards can cut fingers easily. I used a very fine metal sandpaper to remove the shards. Next, place a Hex nut on both sides of the lid and hand tighten before using a wrench to lock them into place.