Vacuum Hose Size Comparison
Vacuum hoses come in different sizes.
Vacuum hoses come in various sizes, and they often play a part in many individual’s buying decisions when shopping for a new wet/dry or shop vacuum.
Smaller diameter vacuum hoses are often more navigable and flexible, not to mention lighter, and for specific applications, there are performance benefits.
Larger diameter hoses can pick up more significant debris, and with less possibility of clogging.
The other day, we talked about some problems we had with our shop vacuum when using it to pick up water. Afterward, we thought about some future testing we required to do, to see how its performance compares with other vacuum types.
With shop vacuum sizes, 2-1/2″ is the right size for overall cleanup tasks. Sometimes a vacuum will come with a smaller hose, sometimes an intermediate size.
Our Festool dust extractor has a 27mm hose, which works great with many handheld power tools, like sanders. Smaller shop vacuums come with 1-1/4″ tubes.
What’s the variance between a 1-1/4″ hose, and a 2-1/2″ hose? The diameter is doubled, and so the cross-sectional area is expanded. (Recall, the area of a circle, is pi*r^2.)
We recently attempted to split the vacuum connection of our dust extractor, so that it could connect to a portable table saw’s lower and guard ports. Most of the dirt was collected through the 2-1/2″ port via our 50mm hose, and the 27mm connection was able to clear the blade guard port, albeit with much-weakened suction. Why? Since we were now asking the vacuum to work with 4.43X, the hose cross-section combined with the 27mm connection, only receiving 22.6% of the full suction power.
Imagine you purchase a small shop vacuum, and it comes with a smaller hose. What happens if you purchase a 2-1/2″ hose to use with it? With the same suction power applied to 4x the hose size (remember, 2x diameter, 4x cross-sectional area), the airflow velocity will lessen.
Some shop vacuums and dust extractors come with intermediate-sized hoses, for maneuverability and attachment advantages, without compromising too much.
With a dust extractor, we found that a 27mm hose works perfectly with sanders and our plunge-cutting circular saw. We purchased a cleaning set and a 36mm hose, which works better with routers. Sometimes, we utilize it with the circular saw, and supposedly performance is supposed to be a little better. And then we have a 50mm hose that functions even better for cleanup tasks. The 50mm also connects to the 2-1/2″ port on specific tools, like portable table saws.
When using a 27mm hose with sanders, we frequently have to dial down the suction, or else there is too much suction power, and the sanding pad can “stick” to work.
In our post the other day, some readers assumed that our use of a wet-rated filter had hampered the vacuum’s performance. While still possible, we think that the 2-1/2″ hose and large nozzles simply couldn’t produce enough velocity to perform as fast and effectively the way we had expected. Switching to a Fein, with its 1-1/16″ (27mm) and smaller nozzle, led to higher airflow velocity.
We probably would have seen better performance from the shop vacuums if we had swapped things over, but the shop vacuums had other downsides that would have led us to reach for the Fein anyway, like the lack of a good top handle.
We have taken tube sizing for granted. We figured it would help to create a visualization because working out differences on paper (yay, math!) might not always be apparent.
With our router table, we’ve wanted to add a below-table box, to aid better contain the dust. Many product manufacturers recommend their under-table dust accessories be used with a 4″ hose, but they don’t explain why.
Surely, we can just branch off our dust extractor, correct? Or even use a second one?
Small diameter hoses work better with
smaller handheld power tools.
A 4″ hose is recommended so that it moves sufficient air to cool down the router motor, at least that’s the consensus on woodworking forums. If there’s not adequate airflow, there’s no escape for built-up heat, and the router motor could be damaged.
Why not utilize a second shop vacuum or dust extractor with a step-up adapter? A 4″ hose is 60% wider, with 2.56X the cross-sectional area. Remember, many larger shop vacuums and dust extractors are designed to work with 2-1/2″ hose diameters – at the most. There’s a good possibility that there just wouldn’t be enough airflow.
Selecting the correct vacuum hose for the job is tough.
A smaller diameter hose, such as 1-1/4″ or 27mm, will often work better with smaller handheld power tools, like sanders, jigsaws, and even circular saws (at least those with dust ports).
A medium diameter hose, like 1-1/2″, 1-7/8″, or 36mm, is a good middle-ground for cleanup tasks, and tools produce lots of chips and dust that can clog smaller hoses, like routers.
A larger diameter hose, like 2-1/2″ or 50mm, is excellent for general cleanup tasks, and for connecting to tools with similarly sized dust ports. You don’t need to use a step-down adapter if you could help it.
Utilize a small hose on leaves, and you’ll spend a lot of time sweeping over an area, and then cleaning out the clogs. Use a large hose on fine dust or water, and you might lose enough airflow velocity to hinder performance.