In today’s stone fabrication and porcelain installation market, the demand for reliable brazed diamond core drill bits is growing rapidly — especially for porcelain slabs, sintered stone, and engineered quartz.
Yet many buyers focus only on price or appearance. In reality, two drill bits that look identical can perform very differently in the field.
If you’re sourcing or selecting a diamond drill bit for porcelain or quartz, there are two things that matter most:
The real quality of the brazed structure
The correct grit size for your material and working condition
What Defines a High-Quality Brazed Diamond Drill Bit?
Unlike electroplated tools, a brazed diamond core drill bit uses high-temperature brazing alloy to metallurgically bond diamond particles to the steel body. This bonding strength is the core of performance.
Here are the practical indicators professionals look at:
Diamond retention under load
A good brazed bit should maintain cutting ability across multiple holes without rapid smoothing. If the surface becomes shiny and inactive after a few holes, the brazing bond is weak or the diamond grade is low.
Uniform diamond distribution
Diamonds must be evenly distributed. Clusters create vibration, uneven drilling, and edge chipping — especially in brittle porcelain tiles.
Controlled diamond exposure height
Too much exposure makes the bit aggressive but fragile. Too little exposure reduces cutting speed and increases heat. Proper protrusion allows efficient dry drilling while maintaining structural stability.
Consistent brazing layer
Professional manufacturers control brazing temperature and alloy flow. Inconsistent brazing often leads to premature diamond loss in high-density quartz drilling.
When drilling dense materials such as 20mm porcelain slabs or engineered stone, these details become immediately visible in cutting stability.
Understanding Grit Size in Brazed Diamond Drill Bits
When people search for “best grit for quartz drilling” or “diamond hole saw for tile,” they often misunderstand what grit actually changes.
Grit size affects:
Cutting speed
Edge finish quality
Heat generation
Tool lifespan
Lower mesh numbers mean coarser diamonds.
Higher mesh numbers mean finer diamonds.
Common ranges:
30/40 or 40/50 mesh – Coarse
60/80 mesh – Medium
80/100 mesh and above – Fine
Coarse Grit: Faster Material Removal
Coarse grit is typically chosen for:
Thick granite
Engineered quartz
Heavy-duty fabrication work
Larger diamond particles cut more aggressively, increasing drilling speed. However, hole edges may be slightly rougher, and vibration can increase if machine control is poor.
For structural drilling where edge aesthetics are not critical, coarse grit often provides lower cost per hole.
Medium Grit: The Balanced Option
The 60/80 mesh range is widely used in the European and Middle Eastern markets for drilling porcelain slabs and sintered stone.
It offers:
Stable cutting speed
Controlled edge quality
Reduced chipping risk
Balanced tool life
For installers searching for the “best diamond drill bit for porcelain tile,” this grit range is often the safest and most versatile choice.
Fine Grit: Cleaner Edges, Slower Cutting
Fine grit (80/100 and above) is typically used when:
Drilling thin porcelain tiles
Visible installations require clean hole edges
Chipping must be minimized
The trade-off is slower material removal. In dense quartz, excessive pressure with fine grit may increase heat build-up during dry drilling.
Matching Grit Size to Material Hardness
A practical guideline used by many fabricators:
Hard and dense material → slightly coarser grit
Thin and brittle material → slightly finer grit
However, grit size alone does not guarantee performance. Diamond quality and brazing integrity always have a greater impact on real durability.
A well-manufactured 60/80 brazed diamond drill bit will outperform a poorly bonded 40/50 bit every time.
Real Application Perspective
In high-volume porcelain slab drilling, contractors often switch from fine grit to medium grit to increase efficiency without sacrificing edge quality.
On decorative tile installations, finer grit prevents micro-chipping that would otherwise require manual finishing.
The key difference is not just grit number — it is whether the brazed structure holds diamonds securely under continuous load.
