This micrograin solid carbide spiral bit is designed for solid woods, wood composites and some plastics. In case a bit doesn't come with a speed chart. You may try the following suggestion. This is merely a guideline to start, result likely varies due to the varieties of edge and material hardness: Run 24,000 rpm maximum for 1" overall diameter router bits; Run 18,000 rpm maximum for 1-1/4" overall diameter router bits; Run 16,000 rpm maximum for 2-1/4" to 2-1/2" overall diameter router bits; Run 12,000 rpm maximum for 3" to 3-1/2" overall diameter router bits; Note : An up-cut spiral bit is used where an upward chip removal and a good finish on bottom are required. When using an up-cut spiral bit, chip removal is optimized but adequate hold down is also needed. A down-cut spiral bit is used where a downward chip removal and a good finish on top are required. A down-cut spiral bit provides downward pressure on the material and leaves an excellent finish on the top.