30" 45Grit Diamond Flat Lap Grinder Grinding Polishing Disk and Laps

Our 30-inch Diamond Disc with Magnetic Backing is engineered for industrial-scale grinding, smoothing, and polishing of large surfaces such as glass, stone, ceramics, and composites. The disc features a precision-coated surface embedded with high-quality industrial diamonds, delivering fast stock removal, excellent surface finish, and long-lasting performance.
The magnetic backing allows for quick and secure mounting onto steel-top grinding and polishing machines, eliminating the need for adhesives or tapes. This makes disc changes fast, clean, and efficient—perfect for high-throughput workshops and professional fabrication environments.
Designed for use with water for optimal results and extended tool life, the 30" diamond disc is ideal for large-scale lapidary work, optical surface preparation, and architectural stone fabrication.
⭐ Product Highlights
Massive 30-inch diameter for large-scale surface work
Precision-bonded with industrial-grade diamond grit for aggressive grinding and polishing
Magnetic backing enables quick disc changes on steel-topped machines
Ideal for glass, stone, ceramics, and composite materials
Compatible with wet grinding systems for cooler operation and longer disc life
Delivers flat, uniform finishes on wide surfaces
Available in a wide range of grits from coarse (60, 100) to ultra-fine (3000+)
Perfect for lapidary studios, fabrication shops, and glass finishing lines
🔧 Machine Compatibility
Fits large flat lap or surface grinding machines (custom or commercial)
Designed for use with machines that accept 30" diameter discs
Requires a ferrous steel top or magnetic master plate for magnetic adhesion
Works best with machines featuring water drip systems or flood cooling
💎 Available Grit Options
Coarse: 60, 80, 100 – for heavy stock removal
Medium: 180, 220, 320 – for shaping and smoothing
Fine: 600, 800, 1200 – for pre-polishing
Very Fine: 3000, 8000, 14,000 – for polishing and final finishing
Custom grits available upon request.
🛠️ Recommended Accessories
30" Steel Master Lap: Heavy-duty ferrous steel plate to support magnetic discs
Magnetic Backing Plate with PSA (Pressure Sensitive Adhesive): Allows temporary PSA disc use while retaining magnetic compatibility
Felt or Resin Polishing Pads with Magnetic Backing: For final oxide or diamond paste polishing
🌊 Usage Notes
Always use with water to prolong disc life and improve performance
Clean both the magnetic disc and steel plate before mounting to ensure full adhesion
Avoid dry use—heat buildup can degrade the bonding matrix and wear the diamond layer prematurely