Shop Vacuums - Canadian Woodworking Magazine

Tool Purchasing 


Shop Vacuums

Whether you use an official dust collection system in your workshop or not, you are bound to need a shop vacuum. While these units won't keep up with large volumes of wood shavings from machines like jointers and planers, they might provide adequate dust collection for smaller machines like routers, sanders or even bandsaws. More importantly, a shop vacuum is an indispensable clean-up tool. I have two in my workshop. One is a larger unit I use to vacuum up messes at certain workstations, or simply to vacuum the floor before embarking on finishing work. The second vacuum is much smaller and nice to take to a client's home for one of those slightly messy installations. It is lightweight, easy to carry and barely takes up any room in my workshop.
Hose Diameter and Accessories
Most shop vacuums come with at least one piece of hose around seven feet in length. Annoyingly, only a few models come with wands, nozzles and other attachments. Many brands consider these items to be accessories, even though most people I know use them. In any event, look for a wide range of available accessories, even if you have to buy them separately. And if the vacuum has on-board storage for some of them, that certainly helps simplify organization.

Hose diameters vary quite a bit from one model to another. I've seen hoses as little as 1" up to 2½" and at least a couple of sizes in between. Small sizes are suitable for fine dust. Larger sizes work better for larger wood shavings or even larger objects like bits of drywall or wood. My smaller vacuum has a small diameter and it's really annoying when I try to vacuum up hand plane shavings, only to have the pipe clog up constantly in the ribbed hose.

Some brands also offer a positive locking tab on the hose, which is very handy. One tends to pull these things around by the hose quite often, so a hose that stays locked to the vacuum is appreciated.
Power and Air Flow
I've frequently mentioned in other articles that horsepower ratings can be very misleading because manufacturers calculate them in different ways. It is very common to see shop vacuums with ratings like "6.5 peak horsepower", even though a 120 volt plug isn't likely to deliver more than about 2 hp. The number of horsepower measured at complete stall just doesn't interest me. Compare the amperage rating of each vacuum to determine which is most powerful. Some draw only seven or eight amps, while others draw 11 or more.

You should also ask the manufacturer for the number of cubic feet of air per minute (CFM) that can be drawn by the vacuum. Be careful to ask for the CFM rating when the machine has all filters in, as some brands might state the CFM with filters removed (a misleading way to measure it). Whatever number of CFM the vacuum will draw with clean filters installed, will drop even further as the filters become clogged.
Find out what kinds of filters are available for the vacuum you are considering. Most vacuums come with some sort of a filter bag and sometimes a cartridge filter as well (sort of like an automotive air filter). But many models now have small micron filters installed or available for purchase. Some micro-filters will filter down to 0.3 microns, whereas the regular ones will be most effective on particles from about 3 to 5 microns. Still other vacuums give the option of HEPA filters, helping to clear the air of even bacteria, mould and pollen.

Some shop vacuums even have filter cleaning features, like electro-magnetic pulses that shake the filter clean. Very handy indeed. I can't tell you how quickly my shop vacuum loses suction, requiring me to clean the filters constantly. And if you open up the vacuum in your workshop to bang on the filters, it won't be long before you realize that you're creating more dust than you’re collecting!
I often joke with students that the loudest tool in my entire workshop is my smaller shop vacuum, but I think it is actually true! I wear ear protection regularly, but especially when using one of these vacuums. Most vacuum manufacturers can give you a decibel rating for each model. Be careful, though, about how that is measured as well. In other words, was the decibel rating measured three feet from the machine, or six feet? The closer you are, the louder the vacuum will be. So be sure to compare apples with apples.

Vacuum manufacturers have come a long way to providing lower noise levels in several models, though they tend to be more expensive machines. One other factor is that vacuums with lower noise ratings don't always have a blower port. The noise level is sometimes reduced by exhausting air in a more diffuse way around the vacuum's housing, rather than out of a single port. If having a blower option is important to you, check on it before making a purchasing decision.
Wet and Dry Capacity
More often than not, shop vacuums are sold with both wet and dry functions. This allows you to vacuum up dry waste, but still have another option when your washing machine unexpectedly overflows. Usually, a squeegee attachment is provided, or available, for wet pick-up. A drain valve allows you to empty the tank easily as well, since many gallons of water weigh a lot. Some manufacturers provide specs on “static water lift” to give you an idea of how effectively it can pump water.

You also need to know how many litres or gallons of waste the vacuum can hold. Some smaller shop vacuums might hold only four or five gallons, while others might hold 16 gallons or more. Remember that vacuums tend to have far less suction once the tank is over half full. So buying a larger size sometimes pays dividends in terms of suction, as well as not having to empty the unit too often.
Automatic Tool Switch/Outlet
One really nice feature you'll find on some models is an outlet on the top of the vacuum into which you can plug a tool. When you turn on the tool, the vacuum turns on automatically. This feature will generally be found only on more expensive models, but it is really handy. Often, people forget to turn the vacuum on before starting up their tool. Or every time you turn off the tool you have to walk several feet to turn off the loud vacuum. Annoyances like that really wear you down and waste time. They also make you less likely to use the vacuum.
Amperage Control
Bosch's new model 3931A includes an ingenious new feature they call their Power Broker™ system. With the turn of a dial, you can decide on how many amps you want the vacuum to use. So let's say you have the vacuum plugged into a 20 amp circuit and you've plugged a 12 amp tool into the vacuum's tool activation port. You dial the vacuum down to just eight amps and you manage to run both the vacuum and the power tool on the same outlet without tripping a circuit breaker. If the power tool uses less amperage, you can dial up the vacuum to its maximum level of 11 amps.
Other Handy Features
There are many other handy features to consider when buying a shop vacuum. One is whether the unit has a handle to move it around easily. This is particularly useful for some of the larger shop vacuums. A large tank capacity can mean a lot of weight when full, particularly when used as a wet vacuum.

Take a look at the wheel sizes as well. Most shop vacuums have small casters. But some have a couple of small casters on the front and larger wheels at the back. This can help you navigate the vacuum over bits of debris, power cords or simply rough concrete floors. Rubber tires are a real bonus. Once again, this sort of feature just makes the tool more convenient and enjoyable to use. Look at other issues like the power cord length. As far as I'm concerned, the longer the better. And weight is something to consider too if you frequently carry your shop vacuum to the job site.
Dust Collection
You don't necessarily need a large dust collection system if you have a small shop and primarily use hand or portable power tools. The Shop-Vac Sawdust Collection System (801-75) uses 2" rigid piping connected by a series of mini blast gates, elbows and "T" fittings, all connected to your shop vacuum. The Shop-Vac system consists of eight clear 3' pipes (24 linear feet), five couplings to join the pipes, four "T" connectors, six blast gates, two 90º elbows and three 45º elbows, ten mounting clamps, along with sufficient wall plugs and screws to mount the system to your shop walls. No glue required – the pipes assemble with a snug friction fit. Which means you can easily move it around if you re-arrange your shop or move to a new one. The system is a breeze to install and works surprisingly well. An excellent alternative to a commercial dust collector and easy on the wallet at $99.99. You can purchase additional components to expand the system as needed. Available at most building supply stores. - CWM


Note: Prices listed in this review were correct at time of printing, but may not reflect current prices. See links/retailer for updated prices.

Standard Shop Vacuums
Ridgid WD1450 Pro Vac
Sears 29620
General 10-300M1
Shop-Vac 962-31

Auto Start Models
Milwaukee 8936-20
Porter Cable 7812
$449.00 - $499.00
Fein_97725Turbo III
Fein 97725 Turbo III
Bosch 3931A Power Broker

Hendrik Varju