No Products in the Cart
Selecting the correct grit size for a diamond milling wheel is one of the most critical decisions in stone fabrication, restoration, and surface preparation. The grit directly influences cutting speed, surface finish, tool life, and overall project efficiency. While many professionals know the basics of “coarse versus fine,” the specific relationship between grit size and stone type often gets overlooked. This guide provides a detailed breakdown of how to match grit size to granite, marble, engineered stone, and concrete, with practical tips for avoiding common mistakes.
Grit size refers to the size of the diamond particles embedded in the wheel’s bond. Coarse grits (e.g., 30–60) cut aggressively, removing material quickly but leaving deeper scratches. Fine grits (e.g., 120–200 and beyond) refine the surface, creating smoother finishes but requiring more passes. Choosing incorrectly can result in excessive tool wear, poor finish quality, or unnecessary labor costs. For example, using a 50-grit wheel on soft marble can cause chipping, while using a 200-grit wheel on hard granite may slow progress drastically.
Granite’s hardness and density require careful grit selection. Start with 50–70 grit for heavy calibration or leveling. For standard surface texturing, 100 grit is often optimal, while 200 grit is reserved for pre-polishing stages. Choosing a too-coarse grit risks micro-cracks, while too fine slows productivity. If you’re calibrating slabs with a 14-inch silent core diamond milling wheel, grit 70–100 offers the best balance of speed and surface quality.
Marble is softer and more prone to edge chipping. Coarse grits should be avoided unless removing heavy stock. Start at 100 grit for controlled calibration and move quickly to finer stages like 200 grit for uniform finishes. The goal is to minimize surface damage while preparing for polishing compounds. Using 6-inch bush hammer plates on marble surfaces is less common but can be used for decorative texture, where grit equivalence plays a role in determining the roughness pattern.
Engineered quartz combines hardness with resin binders, making grit choice critical. Starting too coarse can burn resin, leaving unsightly marks. Grits between 70 and 120 are best for leveling, followed by finer grits for polish prep. Tool cooling and steady pressure are essential to prevent surface burn. A SDS Plus bush hammer tool may be used for aggressive removal, but follow up with the correct diamond grit wheel for finishing.
Concrete varies significantly by mix, age, and hardness. For surface preparation, start with coarser grits (30–50) to remove laitance or coatings. Medium grits (70–100) refine the surface, preparing it for overlays or sealers. Finer grits (150–200) are used only when a smooth finish is required, such as polished concrete floors. SDS Max bush hammer tools and 5-inch bush hammer plates are particularly effective for creating slip-resistant profiles before switching to diamond milling wheels of 70 grit and above.
Many fabricators misuse grit size by over-relying on coarse tools for faster removal. This often damages the stone, leaving deep scratches that are time-consuming to fix. Another mistake is skipping grit stages, which results in uneven surfaces and poor adhesion for coatings. Using bush hammer tools on stones like marble without considering the grit equivalence can also cause irreversible surface damage.
Choosing the right grit size for diamond milling wheels requires more than guesswork. It demands an understanding of stone properties, project requirements, and tool compatibility. By carefully selecting grit size by stone type, professionals can save time, reduce costs, and deliver superior finishes. Whether preparing concrete for overlays, leveling granite slabs, or refining marble surfaces, grit size is the hidden factor behind consistent results.
