Product Description
The CMT 191.503.11 Solid Carbide Upcut Spiral Router Bit is a precision-ground, 2-flute cutting tool engineered for CNC routing machines, router tables, and handheld routers where clean bottom-face finishes and efficient chip evacuation are critical. Built entirely from a special super-micrograin carbide formulation, this 3/8 in. diameter bit delivers a keen, long-lasting cutting edge through deep pockets, through-cuts, and slots in a wide range of wood-based and composite materials. The low-angle upcut spiral geometry shears wood fibers cleanly while pulling chips upward and out of the cut, keeping the work surface clear and the tool running cooler during demanding routing operations.
Key Features
- Super-Micrograin Solid Carbide Construction - the entire bit body is manufactured from a special super-micrograin carbide formulation that produces and holds a keen cutting edge longer than standard carbide, supporting more resharpenings and lower long-term tooling cost.
- Low-Angle Upcut Spiral Geometry - specifically designed to shear wood cleanly rather than tear it, delivering smooth, crisp bottom-face finishes in slots, dadoes, pockets, and through-cuts.
- Upward Chip Ejection - the upcut spiral pulls chips up and out of the cut path, preventing chip packing in deep pockets and blind slots, which reduces heat buildup and keeps cuts cleaner throughout the operation.
- Cooler-Running Design - the combination of the low-angle spiral and efficient chip clearing means the tool dissipates heat more effectively, extending cutting-edge life and reducing the risk of burning in hardwoods and dense composites.
- 1/2 in. Shank Diameter - the full 1/2 in. shank provides maximum rigidity and minimal runout in standard router collets, translating to smoother cuts and reduced vibration during CNC or handheld routing passes.
- 2-Flute Configuration - dual cutting edges balance material removal rate with surface finish quality, making this bit versatile across softwoods, hardwoods, plywood, MDF, chipboard, laminates, melamine, and plastics.
- Right-Hand Rotation - compatible with the standard right-hand collet direction of virtually all CNC routers, router tables, and handheld routers for straightforward, no-adapter installation.
Why This Product
- When routing deep pockets or long slots, chip packing is a common cause of burning and bit breakage - the upcut spiral geometry of this bit actively ejects chips upward with every pass, keeping the flutes clear and the cut path open.
- The super-micrograin carbide formulation holds a sharper edge through more linear footage than conventional carbide blends, making this bit a cost-effective choice for production CNC work where resharpenings extend tool life significantly.
- The 1 1/4 in. cutting height paired with the 3/8 in. diameter gives this bit the reach for full-depth passes in sheet goods and solid wood panels while maintaining the stiffness needed to resist deflection at typical router speeds.
- The low-angle spiral shears rather than scrapes wood fibers, which is especially valuable when routing hardwoods, melamine, and laminated panels where tear-out on the cut face would require additional sanding or finishing steps.
Specifications
- Manufacturer Part Number: 191.503.11
- Brand: CMT Orange Tools
- Diameter: 3/8 in.
- Cutting Height: 1 1/4 in.
- Total Length: 3 1/4 in.
- Shank Diameter: 1/2 in.
- Number of Flutes: 2
- Rotation: Right-Hand (RH)
- Blade Material: Solid Carbide (Super-Micrograin)
- Product Type: Upcut Spiral Router Bit
Approved Applications
- CNC Routing
- Through-Cuts in sheet goods and solid wood
- Deep Pocket Routing
- Chip Evacuation Routing in deep slots and dadoes
- Router Table Operations
- Handheld Router Operations
Compatible Materials
- Solid Hardwood
- Softwood
- Plywood
- MDF
- Chipboard
- Laminates
- Melamine
- Plastic
Frequently Asked Questions
What is the difference between an upcut spiral bit and a downcut spiral bit, and when should I use this one?
An upcut spiral bit pulls chips upward and out of the cut, which is ideal for deep pockets, through-cuts, and slots where chip evacuation is a priority. It produces the cleanest finish on the bottom face of the cut. A downcut bit pushes chips downward, which benefits top-face finish but can cause chip packing in deeper cuts. Choose this upcut bit when routing deep slots, pockets, or performing through-cuts where a clean bottom surface and clear chip path matter most.
What makes the super-micrograin carbide formulation in this bit different from standard carbide?
The special super-micrograin carbide formulation used in this bit is specifically engineered to produce and hold a keener cutting edge compared to conventional carbide grades. The finer grain structure means the cutting edge stays sharper longer through more routing passes, and the bit supports more resharpenings before it needs to be replaced - lowering the overall cost per cut in production routing environments.
Is this bit compatible with my CNC router, router table, and handheld router?
Yes. The 1/2 in. shank and right-hand rotation of this bit are compatible with the standard 1/2 in. collets found on CNC routing machines, router tables, and handheld routers that use right-hand (standard) rotation. Always verify your machine accepts a 1/2 in. shank collet before installing.
Why does the low-angle spiral design help the bit run cooler?
The low-angle spiral is designed to shear wood fibers cleanly rather than scraping or compressing them, which reduces the friction and heat generated at the cutting edge. Combined with the upcut geometry that actively ejects chips away from the cutting zone, less heat accumulates in the flutes and at the tip - extending cutting-edge life and reducing the likelihood of burning in dense hardwoods or composite panel materials.
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