Resin Bond Diamond & CBN Grinding Wheels for CNC Toolrooms: 11V9 vs 4A2 Cup & Dish Wheels
Resin Bond Diamond & CBN Grinding Wheels for CNC Toolrooms: 11V9 vs 4A2 Cup & Dish Wheels
August 5, 2026
Quick Answer: For CNC tool and cutter grinders (ANCA, Walter, Rollomatic, Deckel), the two workhorse wheel shapes you need to know are the 11V9 Flaring Cup and the 4A2 Dish Wheel. The 11V9 cup wheel (commonly #180 grit) is your go-to for rough grinding carbide end mill flutes and OD relief — its flared shape provides clearance for deep grinding. The 4A2 dish wheel (commonly #320 grit) is for finish grinding and end-face operations — its shallow dish profile gives excellent access to tight tool geometries. In Resin Bond, Diamond wheels handle carbide/PCD/CBN inserts, while CBN wheels handle HSS and hardened steels. This guide breaks down shape selection, grit strategy, and bond chemistry for modern CNC toolrooms.
11V9 Flaring Cup vs 4A2 Dish Wheel: Shape & Application
Factor
11V9 Flaring Cup Wheel
4A2 Dish Wheel
Shape Description
Tapered cup — rim extends outward at an angle (typically 70°–80° included)
Shallow dish — flat abrasive rim on a recessed hub (typically 60°–70° included)
Best Grinding Operation
OD (outside diameter) grinding, flute grinding, relief grinding on end mills and drills
End-face grinding, bottom grinding, gashing, notch grinding on cutting tools
Clearance Advantage
Flared shape prevents rubbing against the tool shank during deep flute grinding
Recessed hub prevents interference when grinding tool end faces and small radii
Typical CNC Machine
ANCA, Walter Helitronic, Rollomatic GrindSmart, Deckel S0/S11
Same machines — often loaded as wheel #2 in a multi-wheel changer
Common Dimensions
100mm–150mm OD × 10mm–20mm width × 20mm–32mm bore
100mm–150mm OD × 3mm–6mm abrasive depth × 20mm–32mm bore
Recommended Grit Range
#120–#240 (rough); #270–#400 (semi-finish)
#270–#400 (semi-finish); #500–#1200 (finish)
Resin Bond Diamond vs Resin Bond CBN: Material Match
Carbide end mills, PCD inserts, carbide drills, carbide reamers
Resin bond is self-sharpening — the resin wears slightly during grinding, exposing fresh diamond grains for consistent cutting action. Ideal for the hard but brittle materials Diamond is made for.
CBN is chemically inert to iron — no carbon diffusion wear. Resin bond keeps grinding temperatures low, protecting the HSS from losing temper (critical for tools hardened to HRC 62–67).
The Standard 2-Wheel CNC Toolroom Setup
🛠️ Most CNC Toolrooms Run This Configuration:
Position
Wheel
Grit
Bond
Job
Wheel #1 (Rough)
11V9 Flaring Cup
D180 / #180
Resin Bond
Flute grinding, OD relief, stock removal
Wheel #2 (Finish)
4A2 Dish Wheel
D320 / #320
Resin Bond
End face, gashing, finish passes
💡 With this 2-wheel setup, a 5-axis CNC grinder (like an ANCA FX5 or Walter Helitronic) can grind a complete carbide end mill — flute, OD, end face, and gash — in a single clamping. The 11V9 handles the bulk of material removal; the 4A2 finishes the critical end geometry. Both wheels use the same bore size so they share a single arbor adapter set.
Grit Size, Concentration & Resin Bond Hardness Explained
Parameter
What It Means
Common Range for CNC Toolroom
How to Choose
Grit Size (Mesh)
Particle size of the Diamond/CBN abrasive
D120/D180 (rough) → D320/D400 (finish)
Lower number = coarser, faster stock removal. Higher = finer finish, smaller corner radii possible
Concentration
Amount of abrasive in the bond (C100 = standard)
C75 (light) → C100 (standard) → C125 (heavy)
Higher C = more abrasive grains per volume, longer life, slightly slower cut. C100 is the sweet spot for most toolroom applications
Bond Hardness
How firmly the resin holds the abrasive grains
J (soft) → N (medium-hard) → R (hard)
Softer bond = faster grain exposure, cooler grind, shorter life. Harder bond = longer life, but more heat. N-grade suits most CNC tool grinding
Quick Decision Guide
Grinding carbide end mills and drills on an ANCA/Walter? → Start with 11V9 Resin Diamond D180 + 4A2 Resin Diamond D320
Sharpening HSS gear cutters and broaches? → Use 11V9 Resin CBN B180 + 4A2 Resin CBN B320 instead
Single-wheel budget setup? → Buy the 11V9 D180/Diamond first — it handles 70% of toolroom grinding operations
Need surface finish Ra < 0.2μm on carbide? → Add a 4A2 Resin Diamond D800–D1200 finish wheel
Custom bore size for your grinder? (ANCA uses 31.75mm, Walter uses 20mm, Rollomatic varies) → RONGDA manufactures wheels with your exact bore specification. Contact us with your machine model →
About RONGDA DIAMOND TOOLS: We supply Resin Bond Diamond and CBN grinding wheels in 11V9, 4A2, 12V9, 1A1, and custom profiles for all major CNC tool grinder brands — ANCA, Walter, Rollomatic, Deckel, Schneeberger, Star, and more. Standard grits D64–D1200, custom bonds available. ISO 9001 certified manufacturing. OEM/ODM welcome — send us your wheel drawing for a custom quote.Request a quote →
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