Diamond Dot Discs with Magnetic Backing

Professional diamond dot discs with magnetic backing for flat lap machines and horizontal lapidary grinders. The specialized dot-pattern diamond layout creates open channels across the cutting face, dramatically improving water flow, flushing mineral swarf, and eliminating hydrodynamic hydroplaning. This pattern reduces heat buildup, extends disc longevity, and ensures consistent cutting rates across long grinding sessions. Available in diameters from 6" to 24" across grit 60 to 600, featuring a flexible magnetic rubber backing for instant snap-on attachment to steel master plates. 8" discs are also offered with PSA adhesive, plain backing, and rigid master lap mounts.

Available Sizes & Pricing

Diameter Available Grits Backing Options Price
6" (150mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic backing $10.00
8" (200mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic / PSA adhesive / Plain / Master Lap $16.50 – $28.50
12" (300mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic backing $55.00
14" (350mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic backing $65.00
18" (450mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic backing $105.00
24" (600mm) 60, 80, 100, 140, 200, 270, 325, 600 Magnetic backing $195.00

Grit Selection Guide

Grit Range Process Stage Application & Material Removal
60 – 80 grit Coarse grinding Rapid stock removal, flattening sawn slab faces, rough cabochon shaping
100 – 140 grit Medium grinding Edge beveling, contour refinement, removing deep saw marks
200 – 270 grit Fine smoothing Eliminating coarse scratches, establishing flat surfaces
325 – 600 grit Pre-polish prep Satin finish preparation prior to felt, leather, or composite polishing pads

Key Advantages of Dot Pattern Diamond Discs

  • Interconnected Coolant Channels: Water circulates freely beneath the workpiece, delivering continuous cooling directly to diamond contact points.
  • Superior Swarf Evacuation: Rock slurry and glass swarf wash out immediately, preventing disc loading and abrasive clogging.
  • Reduced Friction & Heat: Interrupted surface reduces drag and thermal stress on heat-sensitive materials like opal, obsidian, and turquoise.
  • Quick-Change Magnetic Backing: Peels on and off flat lap steel master plates in seconds without messy spray adhesives or mechanical clamps.
  • True Flat Grinding: Maintains precision coplanarity when mounted to flat steel support laps.

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Frequently Asked Questions

  • Q: What is the primary benefit of dot-pattern diamond discs over continuous-face laps?
    A: Dot discs feature interrupted islands of electroplated diamonds separated by water escape channels. This design allows water to circulate directly beneath flat slabs and cabochons, preventing surface suction (hydroplaning) and flushing out stone swarf immediately. This runs cooler and reduces disc glaze compared to solid electroplated surfaces.
  • Q: How does magnetic backing attach to my flat lap machine?
    A: The discs have a high-strength magnetic rubber backing that clings firmly to any carbon steel or ferrous metal master backing plate. You simply lay the disc onto the rotating plate, and it stays locked in position. Changing grits takes only seconds with zero adhesive cleanup.
  • Q: What sequence of grits should I use for cabochon preforms and slabs?
    A: Start with 60 or 80 grit for rapid flattening and removing saw marks. Move to 120 or 140 grit to refine the surface, then 220–270 grit to smooth out scratches, and conclude with 600 grit to establish a uniform matte surface ready for cerium or diamond polishing.
  • Q: Can large 18" and 24" dot discs be used on vibrating or commercial flat laps?
    A: Yes. Large-diameter dot discs are engineered specifically for commercial flat laps and large slab grinders. The coolant channels are particularly critical on large surfaces where continuous water coverage is difficult to maintain across a broad stone face.