You can achieve good dust collection in your workshop. Stick to these four basic principles and your shop will be cleaner than ever.
1. Collect Dust at the Source
This is one of the most poorly understood aspects of dust collection. You must position the suction hood as close as possible to the source of emission—your lathe, grinder, or other woodworking machinery. It’s crucial that dust be picked up, as it’s generated, and then directed into the collector. If you lose the dust to your shop air, the task of collecting it becomes futile. You will be inhaling that dust and sweeping it from your machines and floor.
2. Maintain Sufficient Air Volume/CFM
You can determine the efficiency of dust capture fairly accurately by a quick visual inspection of your machinery. Inadequate air volume/CFM allows dust from your grinder to escape onto the floor and into the air. Ensuring your ducting is large enough in diameter and efficiently laid out are two ways you can minimize restrictions on airflow.
Most woodworking equipment requires about 250-1000 CFM. The amount of airflow or CFM needed will vary depending on the size and number of woodworking tools running simultaneously. Most average size table saws, planers, and jointers with 2-5 inch diameter ports need approximately 300-600 CFM to clean well. A machine that loses a lot of chips or is emitting a visible plume of fine dust needs more airflow.
For a more comprehensive source on CFM exhaust volumes, we recommend Industrial Ventilation: A Manual of Recommended Practice for Design by the American Conference of Governmental Industrial Hygienists (ACGIH).
Older editions of this manual can be freely found and read in the Internet Archive and while not as up-to-date, are still fundamentally relevant
3. Use a Cyclone Separator
Separating the bulk of the wood waste from the airstream before it reaches the filter keeps the filter from clogging. A collector that dumps all of the dust directly into a filter (using the filter itself as a dust bin) is a very poor design. It will reduce system airflow/CFM and filter efficiency; not to mention that it won’t keep your shop clean. Remember, you are trying to maintain sufficient airflow/CFM at the woodworking machine to prevent dust loss. If the filter clogs too quickly, this becomes impossible.
A cyclone separator can exceed 99% dust separation efficiency, allowing only a very small amount of very fine dust to pass to the filter. The result is that filter cleaning is reduced by a factor of 50 and you maintain a constant, high level of airflow/CFM to the machine.
4. Use a High Quality Filter
The final stage in dust collection is filtering the fine dust. It doesn’t make sense to go through all the trouble of collecting the dust if you still allow the finest dust to pass through the filter and out into the shop air. The smallest dust is the most unhealthy to breathe and when it becomes airborne, inhalation is inevitable.
Effective filtration requires a quality filter media of sufficient quantity/surface area. You want to filter near 100%, down to the smallest particle (10 microns or less in diameter)--what industrial hygienists refer to as the PM10 range.
Filter media certified to a certain standard, such as HEPA, is also a must. Most of the dust collectors sold by Oneida Air Systems come standard with HEPA certified filter media - tested to be 99.97% efficient at 0.3 microns.
Before purchasing a dust collector, there are a few questions you should ask about its filtration.
- What type of filter is supplied?
- What is its efficiency rating?
- Can a specification sheet be provided?
- Has the filter media been tested by an approved third party agency?
Don’t let dust collection be an afterthought. Follow these four fundamentals to ensure a safer, healthier, and more enjoyable workshop environment.
