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Diamond Tooling 101: How to Choose the Right Grinding Segment for Concrete (Bond, Grit, Style)

Diamond Tooling 101: How to Choose the Right Grinding Segment for Concrete (Bond, Grit, Style)

Diamond Tooling 101: How to Choose the Right Grinding Segment for Concrete (Bond, Grit, Style)

If you’ve ever had diamonds glaze, wear out too fast, or leave chatter marks, it usually wasn’t “bad tooling” — it was a mismatch between the concrete hardness and your bond / grit / segment style.

This guide is a contractor-first breakdown of how to choose the right diamond grinding segments for concrete — with a simple field method to test slab hardness using a Mohs scratch kit.

What are diamond grinding segments?

Diamond grinding segments (often called diamond “shoes” depending on mount style) are metal-bond diamond tools designed to cut concrete by wearing the metal matrix and continually exposing fresh diamonds as you grind. 

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Step 1: Define the job goal (because “best segment” depends on the goal)

There are three common goals, and each one changes your best tooling choice:

1) Grinding bare concrete (flattening / leveling / general grinding)

You care about cut speed, control, and how easy it is to leave a consistent scratch pattern.

2) Surface prep for coatings (epoxy, polyaspartic, urethane, etc.)

You care about mechanical profile + cleanliness required by the coating system. Many crews use aggressive metal-bond diamonds (including 16-grit) in coating-prep workflows when it achieves the required surface condition — but the correct reference point is always the coating manufacturer’s prep requirement.

3) Removing coatings / glue / mastic

Standard grinding segments are not always the best first step. Thick coatings and adhesives often load up diamonds, so many contractors start with PCD removal tooling, then transition to metal-bond diamonds once they’re back to sound concrete.

Step 2: Test the hardness of the concrete (so you can choose the correct bond)

The fastest field method: a Mohs scratch test

A concrete scratch test is widely used in grinding/polishing to determine floor hardness relative to the Mohs scale and help choose the correct diamond bond. 

A commonly used kit is the Mohs’ Hardness Test Kit for Industrial Use. The kit includes color-coded metal picks with points covering Mohs 2 through 9, plus hardness plates (3.5 and 5.5) and instructions designed for industrial applications. 

How to use a Mohs kit on concrete (simple + repeatable)

  1. Pick a representative area of the slab (not dusty, not painted).

  2. Start with a lower-number pick, then work upward.

  3. On each step, press firmly and try to scratch the concrete with a short stroke.

  4. Stop when the pick just begins to scratch consistently. That Mohs number is your approximate surface hardness.

  5. Test more than one spot (corners vs field, near joints, areas with different finishing). Concrete can vary across the same floor.

Pro tip (keeps this “real-world accurate”): concrete is a composite (paste + aggregate). If you’re polishing or grinding deep, do a few tests on areas where aggregate is exposed and consider the range you get, not just one number.

Step 3: Choose the bond (this matters more than grit)

Bond is the metal matrix that holds the diamonds. As you grind, concrete dust wears the bond and exposes new diamonds.

The published rule of thumb (and it works)

  • Soft concrete → hard bond tooling

  • Medium concrete → medium bond tooling

  • Hard concrete → soft bond tooling.

Why it works:

  • Hard concrete doesn’t “abrade” the bond much — so you need a soft bond that wears to expose fresh diamonds (prevents glazing). 

  • Soft/abrasive concrete chews tools — so you need a hard bond to slow wear. 

Bond troubleshooting (fast diagnosis)

  • Tool is shiny / skating / not cutting (glazing): bond likely too hard for the slab (or you started too fine). 

  • Tool wearing out insanely fast: bond likely too soft for the slab.

Step 4: Choose the grit (aggression vs control)

Grit influences how aggressively you cut and how deep the scratch pattern is, but the actual result depends on concrete hardness, machine weight, segment layout, RPM, and technique.

Practical metal-bond grit choices

16/20 grit (very aggressive):

  • Fast material removal / fast “opening”

  • Often used when a deeper scratch / stronger texture is needed, as long as it matches the system requirement

  • May require a refinement step depending on desired finish and spec

30/40 grit (most common all-around start):

  • Strong cut with more control

  • Often the safest “default” when you don’t know what you’re walking into

60/80 grit (refining / cleanup pass):

  • Used when you need to reduce the scratch from the previous step or prepare for the next phase of a system

Simple rule:
If you need speed and bite, go coarser. If you need control and a more uniform scratch, go finer — but don’t start too fine on hard concrete or you risk glazing.

Step 5: Choose the segment style (single vs double vs multi)

Segment layout changes stability, scratch pattern, and aggressiveness.

Single segment

  • Most aggressive / fastest cut

  • Higher chance of chatter or gouging on some slabs

Double segment (best “general purpose” choice)

  • Balanced cut + stability

  • Very common choice for contractors who want predictable results

Multi-segment / more contact area

  • More stable and controlled

  • Often chosen when you want a smoother, more uniform scratch

Step 6: If you’re removing coatings — don’t force standard segments to do a PCD job

For thick epoxy, glue, or mastic, many contractors start with PCD removal tooling, then transition to metal-bond diamonds to clean up and hit the target surface condition.

Recommended product-path on your store (simple and high converting):

  1. PCD Removal →

  2. Transition tooling →

  3. Metal-bond segments (bond + grit matched to hardness)

Quick Selection Cheat Sheet (copy this into your job notes)

If you have NO clue what the slab is:

  • Medium bond + double segment + 30/40

If you did the Mohs scratch test:

  • Hard concrete (higher Mohs result): choose soft bond

  • Medium concrete: choose medium bond

  • Soft concrete (lower Mohs result): choose hard bond 

If you want deeper scratch fast (common in many coating-prep workflows):

  • Start coarser (often 16/20) and refine only if the system or finish requires it.

If you’re removing glue/mastic:

  • Start with PCD rather than burning time loading up segments.

FAQ 

How do I choose diamond grinding segments for concrete?

Match bond to concrete hardness (hard concrete = soft bond, soft concrete = hard bond) and then pick grit and segment style based on job goal. 

How do I test concrete hardness on site?

Use a Mohs scratch test kit to scratch the concrete with progressively harder picks until you get a consistent scratch. That gives an approximate hardness relative to the Mohs scale. 

What’s in the Mohs Hardness Test Kit for Industrial Use?

It includes metal picks covering Mohs 2–9, hardness plates (3.5 and 5.5), and industrial instructions/case components designed for rugged use. 

Want the exact right segment in one shot?

If you want us to match tooling fast, send:

  • Your machine / mount style (trapezoid, Redi-Lock, Lavina, etc.)

  • Mohs scratch result (approx)

  • Job goal (bare grind / coating prep / coating removal)

  • Your preferred grit start (ex: 16/20 vs 30/40)

Then we’ll recommend the best bond + grit + segment style from our lineup.