Onsrud 57-390 Downcut Spiral Router Bit 0.75 in Solid Carbide

Product Description

The ONSRUD 57-390 is a downcut solid carbide spiral router bit designed for clean, chip-free surface finishes on natural wood, solid surfaces, and wood composites. With a 0.75-inch cutter diameter and a 1.625-inch length of cut, it drives chips downward into the material, reducing tearout on the top face of the workpiece. The 30-degree helix angle and double-edge geometry provide efficient material removal while maintaining edge quality. At 4 inches overall length and an uncoated solid carbide body, this bit is built for performance in production and shop environments where surface quality matters.

This bit is suited for routing operations on natural wood, solid surface materials, and wood composites in both production shop and custom millwork settings. The downcut flute direction makes it especially appropriate for applications where top-face finish quality is critical, such as dadoes, grooves, and edge profiles in panel processing. A 3/4-inch shank diameter and 2.375-inch shank length provide solid tool holding in standard router collets and CNC router spindles.

Key Features

• Downcut flute type drives chips into the cut, reducing top-face tearout on wood and composite panels
• Solid carbide construction for wear resistance and edge retention in abrasive materials
• 30-degree helix angle balances cutting efficiency with surface finish quality
• Double-edge router style for stable, consistent material removal
• Uncoated finish suitable for natural wood, solid surfaces, and wood composites
• Right-hand cutting direction compatible with standard router spindle rotation

Compatibility

Designed for use in CNC routers and handheld router applications accepting a 3/4-inch shank. Rated for natural wood, solid surfaces, and wood composites per manufacturer material application data.

Installation Notes

Installation and tool changes should be performed with the router or CNC spindle fully powered down and locked out per applicable safety procedures. Use a properly sized collet matched to the 3/4-inch shank diameter and ensure the shank is inserted to the full recommended depth with no contact between the collet and the fluted cutting zone. Feed rate and spindle speed should be set according to the material being routed and the router manufacturer guidelines. Inspect the cutting edges before each use and replace the bit if chipping or wear is present.