BIHUI 20mm Diamond Milling Bit — Refine and Enlarge Holes Without Chipping Drilling the hole is only half the job — getting it to the exact size and shape a fixture needs is where a milling bit earns its keep. The BIHUI 20mm diamond milling bit refines and enlarges drilled holes in porcelain, ceramic, and natural stone, so you can valve openings, pipe penetrations, and larger fixtures cleanly. The diamond bond removes material smoothly, reducing the chipping and edge blowout that ruin a visible penetration. It runs wet or dry and works with standard tools, so it drops into the setup you already have. When you need a range of profiles for shaping and correcting cuts, step up to the Diamond Milling Bit Set. Why Tile Pros Choose It Refines holes: Enlarge and fine-tune drilled openings to exact size Clean results: Diamond bond minimizes chipping and edge blowout For tile and stone: Porcelain, ceramic, and natural stone Wet or dry: Works with standard tools either way Right-sized: 20mm for valve openings, pipe penetrations, and larger fixtures Pro tip: Keep the bit moving and use water to cool it on dense porcelain — heat is what burns a diamond bit and glazes the tile. Ease into the cut rather than forcing it, and let the diamond do the work.
