What’s the Difference Between Plated and Sintered Diamond Drill Bits?

Diamond drill bits are used to create clean, precise holes in materials like glass, porcelain, ceramic, stone, and certain composites. While they can look similar on the outside, two common types—plated and sintered—are made very differently, which impacts their performance, durability, and how they should be used.

This guide explains how each type works, what makes them different, and how those differences affect drilling results.

Quick Answer: What’s the Difference Between Plated and Sintered Diamond Drill Bits?

Plated bits have a single outer layer of diamond grit bonded to the metal surface. Once that diamond layer wears off, the bit becomes a bare metal tube.

Sintered bits embed diamond throughout the entire cutting edge, continuously exposing fresh diamond as they wear — making them longer-lasting, more consistent, and better for heavy or precision drilling.

1. How Each Type Is Made

Plated (Electroplated) Diamond Bits

Plated bits are created by bonding a single layer of diamond grit onto the tool surface using an electroplating process. The diamonds are held in place by a thin layer of metal (often nickel) on top of the bit body.

• Diamond coverage: Surface layer only

• Manufacturing process: Electroplating

• Typical wear behavior: Diamonds erode or break away once the outer layer is worn

Sintered (Metal-Bond) Diamond Bits

Sintered diamond bits are made by blending diamond grit with metal powders and forming the tool under heat and pressure. This creates a solid diamond-metal matrix, embedding abrasive particles throughout the entire cutting edge—not just on the surface.

• Diamond coverage: Through the full wall of the bit

• Manufacturing process: Most commonly hot-press sintering, though other bonding and pressure methods are also used

• Wear behavior: As the bit wears, new layers of diamond are gradually exposed, maintaining consistent performance

Unlike standard sintered tools formed by basic pressing and heating—which can create micro voids or uneven diamond distribution—Gunther Diamond Tools uses a proprietary “growth” process, where the drill bit develops layer by layer within a diamond-metal matrix. This controlled deposition results in a more uniform structure at the molecular level, reducing imperfections and creating a stable, long-lasting cutting edge.

This design gives Gunther bits improved heat tolerance, reduced glazing, and reliable cutting performance—especially when paired with proper coolant delivery such as through-bit systems.

2. Performance and Use

Plated Bits

• Best for: Low-volume drilling, simple tasks, softer to medium-hard materials

• Cutting behavior: Fast initial cutting due to sharp, exposed diamond grit

• Lifespan: Limited—performance decreases significantly once the diamond coat wears

• Heat tolerance: Lower—can overheat easily without water or coolant

• Maintenance: Cannot be restored once worn

Sintered Bits

• Best for: Repeated drilling, hard or brittle materials like porcelain, glass, and stone

• Cutting behavior: More consistent performance over time; diamonds renew as the material wears

• Lifespan: Long—can often outlast multiple plated bits, especially with proper cooling

• Heat tolerance: Higher—benefits from continuous coolant or water supply

• Maintenance: Can be "dressed" if glazed or dulled, restoring cutting edges

3. Coolant and Chip Removal

Proper chip clearing and heat management are critical for both types of tools, especially when drilling harder materials.

• Plated bits often benefit from external water cooling during use

• Sintered bits see optimal performance with a through-bit coolant system—where water or lubricant is delivered directly through the inside of the tool to the cutting surface

This cooling method not only reduces heat and friction but also helps carry debris away from the cutting area, which can prolong tool life and improve hole quality.

4. Cost and Tool Life

Although sintered bits generally cost more than plated bits, they last significantly longer in most applications—especially when used with proper coolant and feed rates.

• Plated bits: Lower cost per tool, but often higher cost per usable hole over time

• Sintered bits: Higher initial cost, but more economical for long-term or higher-volume use

The difference in useful life and performance can be especially important when drilling expensive materials or when consistency and efficiency are priorities.

5. Quick Comparison

Final Notes

Choosing between plated and sintered diamond drill bits depends on the material you’re drilling, your frequency of use, and whether you’re focused more on up-front tool cost or long-term performance.

• For occasional use on softer or less brittle materials, plated bits may be sufficient.

• For repeated drilling in glass, stone, porcelain, ceramic, or composites—especially with water-based cooling—sintered bits offer greater durability, cleaner results, and better performance consistency.

If you'd like help choosing the right system for your material and setup—or want to explore through-bit coolant systems—reach out anytime.

FAQs: Plated vs. Sintered Diamond Drill Bits

Q: Which type lasts longer — plated or sintered?
Sintered bits last significantly longer because diamond is embedded throughout the tool, not just on the outer surface. As the bit wears, new diamond is exposed.

Q: When should I use a plated diamond drill bit?
Use plated bits for lighter jobs, small diameters, single-use drilling, or when cost is the main factor. They’re great for occasional drilling or softer materials.

Q: When should I use a sintered diamond drill bit?
Use sintered bits when you need maximum durability, consistent hole quality, and clean cuts in hard materials like glass, stone, and ceramics — especially for repeated production work.

Q: Why do plated bits wear out faster?
They only have one thin layer of diamond on the surface. Once that layer is gone, the bit loses its cutting ability.

Q: Are sintered diamond drill bits worth the higher cost?
Yes — for frequent drilling or high-value materials, sintered bits reduce scrap, last far longer, and lower your total cost per hole.