By Martin Harris.

Router Table and CNC Dust Collection

Routers, whether in a table or mounted on a CNC gantry, throw dust in a fine, high velocity spray because of how fast the bit spins. That makes them one of the tools where dust collection setup quality matters more than raw horsepower. A router table or CNC with good capture at the bit will run noticeably cleaner than one relying on collection alone to clean up after the fact.

Router table: under-table collection

Most router table cabinets or fences have a dust port somewhere below the table, usually tied to the enclosed area around the router motor. This catches a meaningful share of the debris, since gravity and the router's own downward airflow push a lot of chips and dust down into the cabinet as the bit cuts. An enclosed cabinet with a decent 4 inch port and enough CFM behind it handles this part reasonably well on its own.

Router table: above-table (fence) collection

The part under-table collection misses is dust thrown up and away from the bit during a cut, especially on edge profiling and any operation where the bit is cutting near the top surface of the material. A fence with a built in dust port, positioned right behind the bit opening, catches a lot of what escapes upward. Running both a fence port and an under-table port, tied together with a Y fitting or two separate gates, covers both directions dust actually travels.

If your router table fence does not have a built in port, aftermarket fence dust ports and overhead capture hoods are worth adding, especially if you do much edge work or template routing where the bit stays close to the surface.

CNC dust collection

CNC routers add a wrinkle: the spindle moves across the whole work area rather than staying in one place, so a fixed hood does not work the way it does for a stationary router table. Most CNC dust collection relies on a boot or shoe mounted around the spindle itself, riding along with the gantry and staying close to the cutting point no matter where it moves on the table.

WorkshopCalc's reference numbers put CNC dust collection demand at 500 to 800 CFM, noticeably higher than a router table's 300 to 400 CFM range, and the sourcing notes are clear that hood geometry can dominate the result more than the CFM number itself. A well fitted spindle boot with a tight seal against the material captures dramatically more than a loose one, even with the same collector behind it. If you are seeing dust escape around the base of the boot rather than being pulled up through it, that is usually a seal or brush skirt problem, not an airflow problem.

Common mistakes

• Only running under-table collection on a router table. This catches roughly half the dust problem. Add fence or overhead capture for anything that throws dust upward.
• A CNC boot with worn or missing brush skirts. The brush or flexible skirt around a CNC dust shoe is what seals the gap between the shoe and the material. Once it wears down or goes missing, capture drops off fast even though the collector is doing the same amount of work.
• Undersized hose for a CNC's moving connection. CNC dust hoses have to flex constantly as the gantry moves, which makes them more prone to kinking and airflow loss than a fixed run. Route the hose with enough slack and support that it does not pinch itself during travel.

Recommended gear

For a router table, most small and mid sized dust collectors handle the job fine once both capture points are in place. See my best dust collection system for small shops roundup. For a CNC, prioritize a collector that can sustain the higher CFM these machines call for, and check hose routing and boot fit before assuming you need more horsepower. My CFM calculator can help you check your specific duct run.

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