These inline containers make your shop vacuum or dust collector work more efficiently.
Oneida 4" Super Dust Deputy deluxe cyclone kit

Two-stage cyclone-style dust collectors work better (and cost more) than single-stage machines because their cone-shaped cylinders disrupt airflow, causing heavier debris to fall out before it gets to the filter. Fewer chips in the filter means improved filtration and efficiency. But you can upgrade your system affordably with an inline dust separator to provide the same benefit at a lower cost. Before you buy a separator, here's what you need to know.

How a separator works

Like a cyclone collector, a separator connected between a dust collector or vacuum and a dust-making machine forces heavier chips and dust particles to drop out of the airflow. Lighter particles remain airborne and continue on to the collector or vac for collection and filtration.

Separators come in two styles: cone-shapes that separate primarily above the collection bin, and low-profile lids that separate within the collection bin. Both attach to a bucket or drum, which may or may not come with the separator. Cone separators cost $50–$550, and have inlet/outlet ports from 2" to 6" in diameter. The lid models cost $25–$80, and have 2–4" ports. Match the inlet/outlet sizes to your vacuum or collector hose for best results.

The steeper spirals on a cyclone separator slow airflow quicker than the more passive low-profile lid models. Debris falls out of the airstream sooner and more efficiently, dropping into the collection drum or bin.
Channels in this separator's low-profile lid direct air into a spiral motion within the bucket or bin, slowing the air's speed so debris settles out. Either port on this unit can serve as the inlet or outlet with no performance difference.

The low-profile-type units rely on the air space inside the collection bin to create the separation action. So, as the bin fills, it becomes less effective at separating the dust. To maintain efficient separation, dump the bin before it reaches 34 full. Cyclone separators can go longer between dumpings because all separation occurs above the collection bin.

This low-profile-style separator proves effective and affordable, mounting simply to a common 5-gallon bucket.

Because the bulk of debris never reaches the collector's small collection/filter bag, an affordable 4" portable collector, such as the 1-hp unit shown in the opening photo, operates more efficiently than it would without the separator. However, adding a separator can reduce a collector or vacuum's overall airflow, so keep flex hose lengths as short as possible to minimize this.

You'll get the best results when you use a separator of appropriate size for your vacuum or dust collector. Using a small separator with a large 3-hp dust collector could overpower the separator, pulling large debris right through it or collapse it. Likewise, a shop vacuum will struggle to pull enough dust-laden air through a large separator with a 4" or larger port.

Look for a separator with a foam-rubber or soft-rubber gasket that seals the lid against air leaks, ensuring maximum suction. These can be replaced as they wear over time.

Bin there, done that

The collection bin for your separator can be as simple as a 5-gallon plastic bucket or as fancy as a steel drum. Smaller bins fill faster, but handle easier for dumping, so decide which is more important: frequency or convenience.

Garbage cans aren't designed or built to precise standards, so the can-topper separator lid you buy might not fit or seal well on your existing can. We were unable to find perfect garbage-can matches for two common lid separators, so buy at your own risk.

We like steel collection drums for their durability, but they're costly and can be heavy to dump. For these, we recommend using disposable liner bags that lift out easily. Rigid plastic drums (larger than a bucket) also work well, and generally prove light enough to lift and dump. Fiber drums, because of their lighter weight, are easiest to lift and dump, and store a good amount of debris. But a drum with walls too thin can potentially collapse under the suction of a powerful vacuum or dust collector.

With any solid-material bin, we suggest you cut a small view window near the top and attach a piece of clear acrylic or glass. This lets you see when the bin needs to be dumped. A separator doubles the footprint of your collector or vac, unless you get creative, as shown below.

Minimize a unit's footprint by stacking the separator and vacuum in a shop-made stand designed to fit your components. Ideally, put the vacuum above the separator to minimize hose lengths and restrictions.


  • Dustopper separator kit, no. HD12, $35, Home Depot,
  • Dust Right dust separator, no. 45556, $80, Rockler, 800279-4441,
  • Dust Deputy deluxe cyclone separator kit, no. AXD000004A, $99.95, Oneida Air Systems, 800732-4065,
  • Super Dust Deputy 4" deluxe cyclone separator kit, no. AXD002040A, $219.95, Oneida Air Systems.
  • Super Dust Deputy 5" cyclone, no. AXD002030A, $169.95, Oneida Air Systems.