Hook up the Cyclone DC to portable power tools?

[Jameel Abraham]

I'm ducting my ClearVue and I'm wondering if I should include a run to the bench area?

Anyone ever tried hooking up say a 2-1/2" hose to their DC for use with biscuit joiner or sander?

I've always used a vac with these tools, but now I'm thinking the DC might be better. After all, we hook up the DC to stationary tools with smaller ports, i.e. miter saw, router table.

So what should I do?

[Ken Baker]

You didn't say what size ducting you are running - but let's say you are running 6 inch - then run a few six inch ducts to areas you might use for jigsaws, sanders etc... Then transition the six inch to 2 1/2. Plug your portables into that instead of your shop vac.

[Jim Becker]

It will "work" but not efficiently. Your cyclone is designed to move a lot of air at low pressure. You can't do that with a small drop/hose...small inlet raises the SP very high and there is little air to supply to the system. It's the air that moves the dust and chips, not "suction", when you are dealing with a dust collector/cyclone system.

[Dan Muller]

It will "work" but not efficiently. Your cyclone is designed to move a lot of air at low pressure. You can't do that with a small drop/hose...small inlet raises the SP very high and there is little air to supply to the system. It's the air that moves the dust and chips, not "suction", when you are dealing with a dust collector/cyclone system.

I have seen this mentioned before, but it seems counter-intuitive. If the DC is moving a large volume of air, and you reduce the cross-section of the path it travels through, the air should speed up, and the differential pressure should be higher according to the Bernoulli effect -- greater suction. There are of course greater losses in a smaller hose, but a regular shop vacuum has to contend with that, too. Is it that the type of impellers or motors used in a DC can't keep the same volume of air moving as the resistance to flow rises?

[Mike Spanbauer]

mostly it's due to the "sucking power" of the units. My cyclone is designed to move a LOT of CFM through an 8" pipe, vs. my festool moving a fair amount of air through a 2" pipe.

They key to both is how hard they suck for lack of the technical terminology. Ie.. my 5hp Oneida pulls roughly 13.5"sp with all gates closed, that is the absolute maximum and each gate opened after wards reduces that SP some, while increasing the CFM pulled through the system.

My Festool on the other hand pulls about 108"sp (static pressure of vacuum in a lift) while moving about 110cfm of volume I believe.

In essence, it moves the air MUCH faster, which keeps the bad stuff suspended in the airstream. As Jim mentioned, keeping stuff "floating" is what enables a large DC to work.

Sorry for the silly analogies, hope they helped to make sense though.

mike

[glenn bradley]

I have much better performance from my shop-vac than on my DC with small openings. 1.5" and 2.25" ports is an area where vacuums are in their element. My ROS draws so well I can actually see stuff getting sucked toward it as opposed to dust flying away.

As a side note; some smaller tools can have too much vacuum assist. I have a collar that allows a controlled "leak" when using my ROS or the vacuum actually fights the rotary action.

[Jameel Abraham]

Great info guys, thanks.

I always had a hard time grasping the whole static pressure vs. suction theory. Still don't!

I'll take your guys advice though and stick with my shop vac for small portable stuff. After all, can't really roll around the DC to where I need it.

[Jim Becker]

I have seen this mentioned before, but it seems counter-intuitive. If the DC is moving a large volume of air, and you reduce the cross-section of the path it travels through, the air should speed up, and the differential pressure should be higher according to the Bernoulli effect -- greater suction. There are of course greater losses in a smaller hose, but a regular shop vacuum has to contend with that, too. Is it that the type of impellers or motors used in a DC can't keep the same volume of air moving as the resistance to flow rises?

Dan, yes there is some of that effect, but the DC systems are not designed to work at high SP and effectively lose more and more performance as the SP climbs beyond, oh, say...a colloquial average of 8-11" SP. Vacs, on the other hand, routinely work at very high SP...sometimes as high as 80-100" SP. They are better suited to small ports and narrow "duct" (hose). For some tools, such as router tables, a retrofit to 4" or greater is the solution. For some bench-top tools, you get enough performance through the 2.5" or so port for it to work fine. (My Delta BOSS OSS and Grizzly G1276 combo sander fit that bill) But for smaller, hand-held tools that have very small ports...the vac is the way to go, IMHO.

[Randy Denby]

Basically to do with the impellor /fan type and fan curve. Designed for more suction, then will need more horsepower per size increment. I'm betting if you were to want the same static lift from a 6" dust collector as a vacuum is rated too...it would take 4 or 5 times the power.....and still not have the cfm capability of a regular dust collector.

:o I think I just talked myself in a circle....my head hurts.....

[Brad Shipton]

I am in the midst of installing a cyclone and have been considering the same. I read this in Mr. Pentz's site and now again. I do not dispute this, but it does not compute to me. Is a shop vac impeller spinning faster than 3400rpm like many elec motors? Otherwise this seems to suggest that a shop vac impeller is more efficient. We increase the motor size on a cyclone so we can spin a bigger impeller and increase the pipe size to achieve a balance between the draw, air velocity, and frictional losses in the pipe for chip collection along with fine dust. How does a shop vac generate such a high SP?

[Eric Gustafson]

It will "work" but not efficiently. Your cyclone is designed to move a lot of air at low pressure. You can't do that with a small drop/hose...small inlet raises the SP very high and there is little air to supply to the system. It's the air that moves the dust and chips, not "suction", when you are dealing with a dust collector/cyclone system.

If one opened a 6" or 4" gate further from the DC than the 2 1/2" small tool hose, would the 2 1/2" work well enough to collect the small tool dust? Then, I assume, the rest of the ducting would have sufficient air velocity to move the dust and maintain cyclonic effciency.

[Jason Beam]

Is a shop vac impeller spinning faster than 3400rpm like many elec motors?

YES. Exactly that.

It's all a compromise of efficiency. You have two competing desires - move LOTS of air ... or move air FAST. As with many things, doing both is expensive. It's all a trade-off. Wanna move lots of air? okay, then it's gotta go slow unless you have a ton of horsepower. Want really really fast moving air? Great, just don't try to move too much. Each increase in speed adds resistence to volume and vise versa.

The physics are fairly simple, but I don't think people realize just how hard air is to move. Air itself may be light weight, but that danged air resistence is a tough one if you intend to physically move it. You can't help but hit it smack on when trying to move it. Ever try to carry a sheet of plywood on a breezy day? That's a very small example of the forces going on inside the dust collector.

[Brad Shipton]

Thanks for your reply. I had never looked into the specs on my shop vac. This makes sense.

[Dan Muller]

I'm glad Jameel asked about this, I found the replies enlightening. Thanks.

[Jameel Abraham]

I'm glad Jameel asked about this, I found the replies enlightening. Thanks.

Me too! Great info everybody.