Dust Management & Shop Ecology · 9 min read
Cyclone dust separator sizing: airflow, drum size and hose diameter
A cyclone separator only works as well as the airflow feeding it. Here is how to size the cyclone body, the drum below it and the ducting to match your dust collector.
By SQUAREFORGE Shop Desk · Updated
Key takeaways
- Match cyclone inlet size to your collector's rated CFM, not the other way around.
- Keep duct runs short and use wide-radius fittings to protect airflow.
- A clear top on the drum lets you see fill level without opening it.
Start with airflow, not tool count
A cyclone separates chips by spinning the airstream, and that only works within a certain velocity range. Undersize the inlet for your collector's CFM and separation efficiency drops; oversize it and you lose the static pressure that pulls chips from a router table or sander.
Matching cyclone to collector
| Dust collector rating | Typical inlet size | Best for |
|---|---|---|
| Under 800 CFM | 4-5 in. | Single-machine shops, portable setups |
| 800-1,200 CFM | 5-6 in. | Two-machine ducted shops |
| 1,200+ CFM | 6-8 in. | Multi-drop shops with several stations |
Ducting and fittings
- Use wide-radius elbows instead of tight 90° fittings to keep static pressure loss down.
- Keep the run from the cyclone to the collector as short and straight as practical.
- Seal every joint; a small air leak upstream of the cyclone reduces separation.
Where to put the cyclone
Position the cyclone as close to the center of your ducting runs as the shop layout allows, and leave room underneath to swap a full drum for an empty one without disconnecting hoses.
Dust collection checklist
| Frequency | Tasks |
|---|---|
| Weekly | Empty cyclone drum, check blast gates are set correctly |
| Monthly | Inspect ducting for leaks and loose clamps |
| Seasonally | Check filter condition and static grounding connections |
/ Frequently asked
Do I need a cyclone if I already have a dust collector?+
A cyclone sits ahead of the collector's filter and catches most chips before they reach it, extending filter life and keeping suction higher over time.
What hose size should I run to a router table?+
4 in. hose suits most router tables and handheld tools; larger stationary machines like table saws often benefit from 5-6 in. drops.