Montolit Diamond Countersink Bit — The Finishing Pass That Stops Cracks

Every drilled hole in tile is a stress riser waiting to happen. Sharp, ragged edges are exactly where a crack starts — often weeks later, under a mounted fixture, long after you've left the job. The Montolit Mondrillo FPS is a diamond tapered end mill that chamfers and smooths the edge of an already-drilled hole in porcelain, ceramic, and glass, relieving those stress points so the opening holds up. It refines the hole; it doesn't drill it.

Use it right after your FAJ diamond drill bit or FSB core bit to clean up and strengthen the opening. Two sizes cover the range: 3/16" to 1-3/8" and 1-3/8" to 3".

Why Tile Pros Choose It

• Prevents cracks: Relieves the internal stress around a hole that rough edges cause
• Chamfers and smooths: A finishing tool for existing holes, not a drilling bit
• Materials: Porcelain, ceramic, and glass
• Two-size coverage: 3/16" to 1-3/8" and 1-3/8" to 3"
• Finished look: A clean, beveled edge that reads as craftsmanship under hardware
• Cheap insurance: Thirty seconds now beats a callback for a cracked tile later

Pro tip: Keep it wet and use a light touch — you're easing the edge, not enlarging the hole. A few gentle passes give a clean chamfer without over-beveling the face.