How to Choose the Right Grinding Wheel

Selecting the wrong grinding wheel costs you in cycle time, wheel life, part quality, and scrapped components. This guide walks you through every decision so you can specify the right superabrasive wheel for your application the first time. Not familiar with a term? See our Grinding Glossary for definitions.

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1Abrasive Type
2Bond System
3Grit Size
4Concentration
5Wheel Grade
6Wheel Shape
7Speed & Machine

1

Choose the Abrasive Type: Diamond or CBN?

The most important decision, driven entirely by your workpiece material

Diamond and CBN are both superabrasives but they are not interchangeable. The wrong choice leads to rapid wheel wear, workpiece burn, and poor results. The decision comes down to one primary factor: is your workpiece ferrous (iron-based) or non-ferrous?

Quick Decision Flow
Ferrous metal?
Steel, cast iron, HSS, superalloy
→
Use CBN
Non-ferrous?
Carbide, ceramic, glass, composites, PCD
→
Use Diamond
Why you cannot use Diamond on steel: At grinding temperatures, diamond reacts chemically with iron. The carbon in diamond diffuses into the steel workpiece, destroying the abrasive grain rapidly. This causes catastrophic wheel wear and workpiece contamination. Always use CBN on ferrous materials.
CBN — Cubic Boron Nitride

Use for Ferrous and Hard Metals

Second hardest material after diamond. Chemically stable with iron-based metals at high temperatures.

  • Hardened steel (45–68 HRC)
  • High speed steel (M2, M42, T15)
  • Tool steel (D2, H13, A2)
  • Bearing steel (52100)
  • Cast iron (gray, ductile, white)
  • Superalloys (Inconel, Waspaloy)
  • Camshafts, crankshafts, gears
  • PCBN inserts
Diamond

Use for Non-Ferrous and Hard Brittle Materials

Hardest known material. Chemically reactive with iron — do not use on steel.

  • Tungsten carbide (WC-Co)
  • Technical ceramics (Al₂O₃, Si₃N₄, SiC, ZrO₂)
  • Glass and optical materials
  • Carbon fiber composites (CFRP)
  • PCD (polycrystalline diamond) inserts
  • Flame-sprayed carbide coatings
  • Granite, stone, concrete
  • Semiconductor materials
Cross-over materials: Some materials such as titanium, cobalt alloys, and certain stainless steels can be ground with either CBN or diamond depending on the specific grade and application. Contact a SuperAbrasives engineer for guidance on borderline materials.
Property CBN Diamond
Use on steel Yes No — reacts chemically
Use on carbide No Yes
Use on ceramics No Yes
Thermal stability Up to 1,400°C Up to 700°C (in air)
G-ratio advantage vs. conventional 10–100x 10–1,000x

2

Choose the Bond System

How the abrasive is held affects dressability, finish, form holding, and wheel life

The bond is the matrix that holds abrasive grains together. It determines how the wheel wears, whether it can be dressed, how it handles heat, and what surface finish it produces. There are four bond systems for superabrasives, each with a specific role.

Vitrified Bond

Best for: High-production precision grinding

Glass-ceramic bond fired at high temperature. Rigid and porous with excellent coolant flow. Dressable with rotary or stationary tools. The workhorse of production superabrasive grinding.

  • Camshaft and crankshaft grinding
  • Gear tooth grinding
  • Bearing race grinding
  • Cylindrical OD/ID grinding
  • High-volume CNC applications
Resin Bond

Best for: Fine finish, tool grinding

Thermosetting polymer bond. More flexible than vitrified, cushioning the grinding action for better surface finish. Requires dressing stick or brake-controlled dresser.

  • Cutting tool sharpening (drills, end mills)
  • Carbide insert grinding
  • Fine finish applications
  • Lower production volumes
  • Applications requiring Ra below 16 µin
Metal Bond

Best for: Form holding, long life

Sintered metal matrix (bronze, iron, cobalt). Strongest bond with the highest wheel life. Holds form precisely over very long production runs. Requires EDM or crush dressing.

  • Creep feed grinding
  • Complex profile grinding
  • PCD and PCBN insert grinding
  • Ceramic grinding
  • Applications with tight form tolerances
Electroplated Bond

Best for: Complex forms, interrupted cuts

Single layer of abrasive nickel-plated to a precision steel core. Maximum grit protrusion for aggressive stock removal. Cannot be dressed and is used until the abrasive layer is depleted.

  • Broach grinding
  • Hob grinding
  • Drill flute grinding
  • Slotting and cut-off
  • Prototype and short-run complex forms
Bond Dressable? Surface Finish Form Holding Best Use
Vitrified Yes — rotary or stationary Good to Excellent Excellent Production grinding
Resin Yes — dressing stick or brake-controlled Excellent Good Finish grinding, tools
Metal EDM or crush only Moderate Superior Profile, creep feed
Electroplated Not dressable Moderate to Good Superior Complex forms, broaches
SuperAbrasives’ Maximizer line uses a unique vitrified bond engineered for both rotary and single-point dressing. It bridges the gap between high-production vitrified and flexible job shop use, making it ideal for tool rooms and applications where dressing setup flexibility matters.

3

Select the Grit Size

Balancing material removal rate against surface finish requirement

Grit size is the mesh number of the abrasive grain. Coarser grits remove material faster but leave a rougher surface. Finer grits produce smoother finishes but cut more slowly. Your required surface finish (Ra) and stock removal needs will determine the right grit size.

Grit Size Reference Guide
Extra Coarse
46 – 80
Heavy stock removal, rough grinding
Coarse
80 – 120
Roughing passes, high MRR, 32–125 µin Ra
Medium
120 – 180
General purpose, semi-finish, 16–63 µin Ra
Fine
180 – 320
Finish grinding, 8–32 µin Ra, bearing surfaces
Very Fine
320 – 600
Precision finish, 4–16 µin Ra, tool grinding
Ultra Fine
600+
Mirror finish, below 4 µin Ra, optical and medical parts
Not sure which grit to start with? For most production grinding applications, a medium grit (120–180) is the right starting point. From there, adjust finer for better finish or coarser for more aggressive stock removal. See our Surface Finish Chart for Ra reference values, or call us at (248) 348-7670.

4

Select the Concentration

Volume of abrasive in the bond affects wheel life, cutting force, and cost

Concentration describes the volume percentage of diamond or CBN grain within the bond layer. Concentration 100 equals 25% abrasive by volume (the international standard). Higher concentration means more cutting points per unit area, giving longer life but requiring more machine power.

Concentration Characteristics Best For
25 Very free cutting, low force, fast self-sharpening Fine finishing, low machine power, soft bond resin wheels
50 Free cutting, good finish, moderate life Tool grinding, resin bond general purpose
75 Balanced cutting and life General purpose vitrified, medium production
100 Long wheel life, higher cutting force required High-production vitrified CBN (camshaft, crankshaft), metal bond
125–150 Maximum life, requires high machine stiffness and power Heavy production, electroplated, demanding metal bond applications
Higher concentration is not always better. If your machine lacks the stiffness or power to drive a high-concentration wheel, you will get rubbing instead of cutting. This leads to glazing, burn, and poor finish. Match concentration to your machine’s capability as well as the application demands. See our Troubleshooting Guide if you are experiencing glazing or burn.

5

Determine the Wheel Grade

How firmly the bond holds grains controls the self-sharpening balance

SuperAbrasives uses four hardness grades — N, R, S, and T — from soft to hard. This is specific to our wheel marking system and controls how readily dull grains are released from the bond to expose fresh cutting edges underneath. The right grade is matched to your workpiece hardness and contact area.

Grade Code Hardness Grain Behavior Use When
N Soft Grains release readily when dull, continuously exposing fresh sharp grain Hard workpiece materials (high HRC steel, carbide), large contact area, high wheel speeds, applications where burn risk is a concern
R Medium-Soft Moderate release with good balance of grain life and self-sharpening Medium hardness workpieces, general production OD and ID grinding
S Medium-Hard Grains are retained longer before releasing Softer workpiece materials, smaller contact area, lower wheel speeds, resin bond tool grinding
T Hard Maximum grain retention for longest wheel life in the right application Very soft materials, interrupted cuts, small contact area where wheel life is the top priority
The grade rule: Use grade N (soft) on hard materials like hardened steel and carbide. Use grade T (hard) on softer materials or where the contact area is small. Using too hard a grade on a hard workpiece causes glazing and burn. Using too soft a grade on a soft material causes rapid wheel wear and short life.

6

Select the Wheel Shape

ANSI/ISO geometry determines how the wheel contacts the workpiece

Wheel shape defines the geometry of the abrasive section and how it contacts the workpiece. Standard shapes are designated by ANSI B74.3 and ISO 6104. The most common superabrasive shapes are listed below. See our full Standard Wheel Shapes guide for complete dimensional drawings, or contact us if your application requires a custom profile.

ANSI Shape Description Typical Application
1A1 Straight, flat periphery OD cylindrical grinding, surface grinding, general purpose
1FF1 Face wheel, abrasive on flat face Face grinding, surface grinding on vertical spindle machines
11V9 Flaring cup, V-shaped abrasive section Drill point grinding, tool grinding on universal machines
12V9 Dish, angled thin face Clearance face grinding on cutting tools, broach grinding
14F1 Straight rim, narrow face on hub Slot grinding, plunge grinding, narrow face applications
Custom / Form Profile ground to match part geometry Cam lobes, gear roots, turbine blade roots, thread forms
SuperAbrasives’ Engineered Segment System (ES) allows us to manufacture virtually any wheel shape without the limitations of standard production tooling. Complex forms, large diameters, and unusual profiles are all achievable. The reusable hub system means you replace only the worn abrasive segments, not the entire wheel, saving significant cost on large wheels.

7

Verify Speed and Machine Compatibility

Safety and performance depend on matching the wheel to your machine

Before running any superabrasive wheel, verify that your machine is compatible. Confirm the spindle speed does not exceed the wheel’s maximum rated RPM, that the machine has sufficient power and rigidity to drive the wheel at the required concentration and depth of cut, and that your coolant system delivers fluid directly to the grinding zone. If you are unsure whether your machine is suited to a superabrasive application, contact SuperAbrasives at (248) 348-7670 or visit our Services and Support page and we can advise.

Quick Selection Summary

Step 1 — Abrasive

Ferrous metal (steel, cast iron, HSS) use CBN. Non-ferrous (carbide, ceramic, glass) use Diamond.

Step 2 — Bond

High production CNC: Vitrified. Fine finish / tools: Resin. Form holding: Metal. Complex forms: Electroplated.

Step 3 — Grit

Roughing: 46–120. General purpose: 120–180. Finishing: 180–320. Precision: 320–600+. See our Surface Finish Chart.

Step 4 — Concentration

Low volume or finish work: 25–50. General production: 75–100. Heavy production: 100–150.

Step 5 — Grade

Hard workpiece: Grade N. Medium hardness: Grade R. Softer workpiece: Grade S or T. See our Wheel Marking System.

Steps 6 and 7

Match shape to your operation — see Standard Wheel Shapes. Verify RPM before mounting. Questions? See Services and Support.

Not sure which wheel is right for your application?

SuperAbrasives engineers have been solving grinding problems since 1977. Call us at (248) 348-7670 or send us your application details and we will recommend the right wheel specification. You can also browse our Case Studies to see how we have solved similar applications, or visit the Grinding Glossary for any terms used in this guide.

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