By Martin Harris.

Dust Deputy vs Super Dust Deputy: Which Size Fits Your Setup

The regular Dust Deputy is built for a shop vac. The Super Dust Deputy is built for a dust collector. Oneida Air Systems, the company that makes both, designs the Super Dust Deputy for systems moving more than 350 CFM at less than 10 inches of water column, while a shop vac moves less than 250 CFM at more than 60 inches. So the right one depends on the machine that pulls air through it.

CFM means cubic feet per minute, the volume of air moving through the hose. Static pressure is how hard the fan pulls against resistance. It is measured in inches of water column, which I write as in. w.c. from here on. A shop vac pulls hard through a small hose. A dust collector moves a lot more air through a big hose at low pressure. Each cyclone is shaped for one of those two jobs. Below are Oneida's published specs for each model, how to pick a bin, and how to set each one up.

The four models at a glance

Oneida sells two sizes of the regular Dust Deputy and two sizes of the Super Dust Deputy. Here is what each one is made for, pulled from Oneida's product pages and FAQs.

Source: Oneida Air Systems product pages and Dust Deputy and Super Dust Deputy FAQs. OD means outside diameter and ID means inside diameter. A mil is one thousandth of an inch.

Why a shop vac and a dust collector need different cyclones

A cyclone separator spins the incoming air in a circle. Chips and most of the dust get thrown against the wall, lose speed, and fall into the bin below. The cleaner air turns and leaves out the top. That spin only works when enough air moves through the cyclone body to keep it fast. Matthias Wandel, who built his own separator and wrote it up on woodgears.ca, found that slower circulation means less force on the dust, and less of it separates.

This is why the sizes don't cross over well. Put a shop vac on a Super Dust Deputy 4/5 and you are feeding a cyclone that needs at least 350 CFM with a machine that makes less than 250. The air moves too slowly through the big body, and more dust rides through to the vac filter. Go the other way and put a small Dust Deputy on a dust collector, and the 2 in. or 2.25 in. ports choke a fan that was designed to move a large volume of air at low pressure. The collector's airflow drops, and so does capture at the tool.

If you haven't picked between a vac and a collector yet, my dust collector vs shop vac comparison covers that first choice. The rest of this page assumes you already know which one you run.

Dust Deputy for a shop vac

The Dust Deputy comes in two sizes, and the port on your vac decides which one you want. Oneida says the original Dust Deputy is best for vacs with ports of 2 in. or smaller. The Dust Deputy 2.5 is for vacs with ports of 2.25 in. or larger, and Oneida says it allows up to 2 times the airflow of the original on those vacs.

The 2.5 has a bigger body and bigger ports. Oneida explains that the larger size means less friction for the same air, which means less pressure drop and more flow. Its inlet and outlet measure 2.25 in. ID nominal (2.29 to 2.31 in. actual), and they friction fit the standard 2.5 in. cuffed hose ends that come with shop vacs. The cyclone stands 15.5 in. tall, so add that to the height of your bucket when you plan where it will sit. Oneida says it stops 99% of dust from reaching the vac filter.

Both sizes come as a DIY kit, which is the cyclone with a gasket and mounting hardware and no bucket, or as a complete kit with a bucket and lid. The Oneida Dust Deputy Deluxe is the complete kit I list in my separator roundup, where it measured 112 CFM on a 2.5 in. shop vac setup. For a DIY build, the Dust Deputy 2.5 DIY fits most 2.5 in. vac hoses, and the original Dust Deputy DIY suits smaller vacs with 2 in. or smaller ports.

Check your vac before you order. Measure the inside of the hose cuff where it plugs into the vac, and buy the size that matches. A 2.5 on a vac with a small port gains you nothing, since the small port still limits the air.

Super Dust Deputy for a dust collector

The Super Dust Deputy 4/5 is Oneida's cyclone for small and mid-size single-stage collectors. Oneida rates it for 0.5 to 3 HP collectors with a minimum of 350 CFM. A single-stage collector is one where chips and dust go straight through the fan and into a bag. Adding a Super Dust Deputy ahead of it turns the setup into a two-stage system, since most of the dust drops out before it reaches the fan and the filter. Oneida says it separates up to 99.9% of dust and debris from the airstream.

The ports are flexible. The inlet is 5 in. OD (4.75 in. ID), and an included reducer brings it to 4 in. OD (3.75 in. ID). The outlet is 6 in. OD (5.75 in. ID), with a second reducer that takes it to 4 in. OD. So one cyclone works with a 4 in. hose collector or a 5 in. duct system. The cyclone alone measures 14.25 x 13.25 x 23 in. and weighs 6.5 lb.

Height is the number to check in a garage. Oneida lists the Deluxe kit, with its 15 gallon drum, at 43-5/8 in. tall, with the center of the inlet at 39-3/16 in. Add room above it to lift the cyclone and lid off when you empty the drum. Then add the hose from the cyclone outlet to your collector inlet, and keep that hose short. Oneida's loss data shows 1 ft of flex hose costing about as much static pressure as 5 ft of rigid duct.

For bigger machines, the Super Dust Deputy XL has 6 in. ports and is rated for 3 to 5 HP collectors moving 850 to 1,200 CFM. It stands 37.5 in. tall and weighs 8.45 lb. Most one and two car garage shops run a collector in the 1 to 2 HP range, which puts them in 4/5 territory. If you are unsure what your tools need, the CFM calculator on my what size dust collector do I need page will tell you.

Buying options: the Super Dust Deputy 4/5 DIY is the cyclone only. The Super Dust Deputy 4/5 Deluxe adds the fiber drum with a pre-cut lid, a lid clamp, a gasket, and hardware. The Super Dust Deputy XL is the 6 in. version. The Super Dust Deputy in my separator roundup measured 410 CFM on a 4 in. collector setup.

Matching the inlet to your hose or duct

Use the port size your system already has. On a 1 or 1.5 HP collector with a 4 in. hose, install both 4 in. reducers and run 4 in. hose in and out. On a system with 5 in. duct, leave the inlet reducer off and connect straight to the 5 in. inlet. Resistance climbs fast as duct diameter shrinks, so avoid necking a 5 or 6 in. main down to 4 in. only to fit the cyclone. If your main is 6 in. and your collector is 3 HP or bigger, look at the XL instead.

On the shop vac side it is simpler. Plug the vac hose into the Dust Deputy's top outlet and your tool hose into the side inlet. If the vac hose cuff fits loose, use an adapter rather than tape. A leak at the outlet lets the vac pull outside air instead of air through the cyclone, and separation suffers.

Bin choices for each size

The bin has two jobs. It has to seal airtight, and it has to hold its shape under suction. Oneida says any shape or size of container works for a Dust Deputy as long as it seals, and it suggests foam gaskets or silicone caulk to get there.

For a Dust Deputy on a shop vac, Oneida says a 5 gallon bucket needs a wall at least 90 mils thick (0.09 in.) or it may collapse, and that big box store buckets are too thin. If you only have thin buckets, Oneida's fix is to nest two of them together. The outer bucket keeps the inner one from bulging, so it holds its shape. For wood dust, Oneida suggests keeping the container at 10 gallons or smaller with the regular Dust Deputy.

For a Super Dust Deputy on a collector, the Deluxe kit's 15 gallon fiber drum is a light-duty container. Oneida notes that fiber drums are not typically suited to pressures above 80 in. w.c. and may collapse unless reinforced. A dust collector system for the Super Dust Deputy runs below 10 in. w.c., so that limit is far away. A shop vac can pull more than 60 in. w.c., which is one more reason to keep a vac off a fiber drum. Oneida also sells 35 and 55 gallon steel drum kits, and the 35 gallon kit replaces the fiber drum. Oneida's rule is that the bigger the container, the sturdier its walls need to be.

Liners make emptying easier. Oneida's 1.5 mil liners fit 9 to 17 gallon bins and its 3 mil liners fit 30 to 55 gallon bins. Under a cyclone, a liner has to be held open or it gets pulled up into the cyclone. My guide to dust collector bins, buckets, and liners covers sleeves, liner sizes, and how to empty a bin safely.

Setup steps

1. Seal the lid first. Mount the cyclone to the bucket or drum lid with the included gasket and hardware. Seal any gaps with foam gasket or silicone caulk, as Oneida recommends.
2. Put the bin where you can reach it. You will empty it often, so leave room to unclamp the lid, lift the cyclone, and slide the bin out.
3. Connect the outlet. Run the shortest hose that reaches from the cyclone's top outlet to the vac or collector inlet.
4. Connect the inlet. The tool hose, or your main duct on a collector, goes to the side inlet.
5. Check for leaks. With the vac or collector running, listen and feel around the lid, the ports, and the bin rim for hissing air. Fix every leak before you judge how well it separates.
6. Watch the fill level. Empty the bin before the pile gets close to the bottom opening of the cyclone. Past that point, spinning air picks dust back up and sends it to the filter.
7. Think about static. Oneida sells anti-static and static dissipative versions of the Dust Deputy, which it says carry static charge away to prevent shocks.

Which one I would buy

Match the cyclone to the machine and the vac port first. Then spend what is left of the budget on a good bin.

• Shop vac with a 2.5 in. hose: Dust Deputy 2.5 on a 90 mil bucket, or the Deluxe kit if you want the bucket included.
• Small vac with a 2 in. or smaller port: the original Dust Deputy.
• 1 to 3 HP single-stage collector with 4 or 5 in. hose: Super Dust Deputy 4/5. Move up to a steel drum if you want a bin that holds up better than fiber.
• 3 to 5 HP collector with 6 in. duct: Super Dust Deputy XL.

If you are weighing a cyclone against building your own baffle, read my Dust Deputy vs Thien baffle comparison. For every separator I recommend, with measured airflow and fine dust capture, see my best dust separator roundup. And for how a separator fits into the whole system, start with my complete guide to small shop dust collection.

FAQ