CMT Reduction Ring for Saw Blades - 5/8" x 10mm by CMT is a precision-machined arbor adapter bushing designed to reduce a 5/8-inch (15.87mm) outer diameter bore down to a 10mm inner bore. This saw blade reducing bushing allows woodworkers and tradespeople to mount a 10mm arbor hole blade onto a saw with a 5/8-inch spindle, expanding compatibility across stationary table saws, miter saws, and circular saws without replacing the blade or the tool.

Key Features

• Outer diameter of 5/8" (15.87mm) paired with a 10mm inner bore - bridges the gap between metric blades and standard imperial arbors, giving you a secure, wobble-free fit without modification
• Maximum thickness of 0.047" - the low-profile design seats flush within the blade arbor recess, avoiding interference with the blade flange or clamping hardware
• Adjustable arbor hole compatibility - the circular saw blade bushing adapts the blade bore to match the machine spindle, letting you use a wider variety of saw blades across different tools
• Available in multiple saw blade arbor adapter ring sizes - allows you to build a complete set of reducing bushings for different blade and machine combinations, reducing the need to purchase duplicate blades
• Engineered for use with circular saw blades, table saw blades, and miter saw blades - a single component that covers the most common workshop cutting applications

Why This Product

• Solves a common arbor mismatch problem - when a saw blade has a 10mm bore but your machine has a 5/8-inch arbor, this reduction ring fills that gap precisely, letting you use the blade you already own rather than purchasing a new one
• Compact 0.047" maximum thickness means the ring adds virtually no stack height between the blade and the arbor flange, preserving the blade's intended cutting geometry and clamping integrity
• Designed specifically for saw blade arbor reduction - unlike generic washers or improvised spacers, this is a purpose-built saw blade arbor adapter ring machined to the exact diameter specifications required for a reliable, centered fit
• Part of a broader range of CMT reduction ring sizes - if your shop runs multiple saws and blades with different bore dimensions, CMT offers matching adapters so you can standardize your blade inventory across machines

Specifications

• Manufacturer Part Number: 299.218.00
• Outer Diameter: 5/8"
• Small Diameter: 10mm
• Bore Diameter: 10mm
• Maximum Thickness: 0.047"
• Brand: CMT Orange Tools

Approved Applications

• Arbor bore reduction for saw blades
• Blade compatibility expansion on circular saws
• Blade compatibility expansion on table saws
• Blade compatibility expansion on miter saws
• Adapting 10mm bore blades to 5/8" arbor spindles

Frequently Asked Questions

What does this reduction ring actually do?

This CMT reduction ring acts as an arbor adapter bushing that fits into the center hole of a saw blade. It reduces the blade's effective bore from 5/8" (15.87mm) down to 10mm, allowing a blade with a 10mm arbor hole to be mounted securely on a machine with a 5/8-inch spindle.

Which types of saws is this arbor adapter compatible with?

This saw blade reducing bushing is designed for use with circular saws, table saws, and miter saws. It is intended for any machine where the spindle arbor measures 5/8" and the blade bore is 10mm.

Will the thickness of this ring affect how the blade seats on the arbor?

The maximum thickness of this reduction ring is 0.047", which is a very low-profile dimension. This slim profile is intentional - it allows the ring to sit within the blade bore without adding significant stack height between the blade and the arbor flange, helping maintain proper clamping and blade seating.

Is this reduction ring available in other diameter combinations?

Yes. CMT offers reduction rings in different saw blade arbor adapter ring sizes beyond the 5/8" x 10mm combination. If you need to match a different arbor or blade bore pairing, other sizes are available within the CMT 299 series of reducing bushings.