Most dust collectors are bought on one number: the CFM on the box. The trouble is that number is measured with almost nothing attached. Once you add hose, ducting and a filter, real airflow drops.
Pick the machines in your shop, tell us how you will hook them up, and this calculator shows the airflow you need and the collectors on our store that can deliver it.
How to use it
- Tick your machines.Check every machine you will hook up to the collector. Not listed? Type its CFM in the box under the list.
- Answer two questions.Do you run one machine at a time or several together? And is it a short hose or a duct run?
- Read your answer.The CFM you need shows on the right, with the collectors on our store that can handle it, cheapest first.
Your machines
Every number above is the minimum dust collection the manufacturer lists for that machine. If yours is different, use the number in your manual.
Most small shops run one machine at a time and close blast gates on the rest, so you size for your biggest machine.
Longer runs, bends and smaller pipe all cut airflow, so you need a bigger collector to end up with the same air at the machine.
Airflow you need at the machine
Collector rating to shop for
Collectors on our store that fit
Pick your machines to see matches.
How this is calculated. Machine airflow comes from the minimum dust collection each manufacturer lists for the machines we carry. One at a time uses your biggest machine. At the same time adds them all up. The collector rating is that number times a hookup allowance: 1.25× for a short hose, 1.5× for a duct run up to 25 ft, 2× for longer runs. That allowance is our own rule of thumb, because manufacturer CFM ratings are measured with little or no ducting attached.
Collector ratings used. For JET cyclones we use the lower U.S. test number with filters installed (763, 938 and 1,240 CFM), not the higher European number. Other collectors use the maximum CFM the manufacturer lists. Treat the result as a planning estimate. Your duct layout, the number of bends and how clean your filter is all change real airflow.
Three things the CFM number won't tell you
1. Wood dust and metal sparks never share a collector
A spark from a grinder can smolder in a bag full of sawdust and start a fire hours later. Keep metal grinding on its own metal dust collector, like the JET JDC-501 or the Baileigh MDC-1800.
2. The filter decides what you breathe
A 30-micron bag catches chips but lets fine dust back into the air. A 2-micron canister or a HEPA filter catches the fine dust that stays in your lungs. If you sand a lot, the filter matters as much as the airflow.
3. Planers and drum sanders are the hungry ones
A 15 to 22 in. planer needs 900 CFM and a dual drum sander needs 1,200 CFM. If you own one, size the collector for it first. Everything else in the shop will be covered.
Want us to check your setup?
Send us your machine list and a rough sketch of your shop. We will tell you which collector fits and what size duct to run.
Ask us about your shop or call (888) 990-8016