I feel that you did an excellent job of explaining the basic mechanics of air flowing through a pipe, but completely neglected to say how it applies to this situation! Should one use a larger diameter system of ductwork, only reducing as needed size at the tool? Can diameter be increased/decreased without significant losses? Is there an ideal diameter of the inlet for chip capture based on CFM or horsepower of the system? (duct length and complexity not withstanding). Is there an ideal volume/pressure ratio for chip capture? For airborne dust capture? Is there different CMF/HP/Diameter/airspeed for dust extraction VS chip capturing? How do such systems differ?

Thank you for inspiring the next generation of learners, perfect for our homeschool as we plan and build a dust collection system.

Wow you broke this down to 3rd grade level. At first I was like, "Oh man, here we go. He's gonna put on his white lab coat and talk about the Bernoulli principle with fluid dynamic equations." But this was succinct, accurate and blessedly math free! Thank you!

Nice job, as a retired mechanical engineer I was impressed with the way you showed the principles. Now if you can just solve the miter saw’s problem of miserably poor dust collection.

I’m a nail tech (nail salon owner) making a dust collector instead of spending thousands on a 110cfm fan and this helped so much! Thank you!

Best video on dust extraction I've seen on the web. Thank you.

Totally distracted by the map of Budapest. My wife and I were there four years ago - what a great city full of wonderful people, and incredible history! And thanks for this video; I'm setting up my first real dust collection system. Medium sized shop, voltage limited to 120V, so efficiency will be crucial.

You have been an inspiration to me. I read your book three times. Actually took two classes at 2nd year HVAC engineering level. I have two Ph.D.s and a law degree (no joke). I made a ton of money on tech stocks so I allocated $3M to build a sawmill, dry kiln, millworks and all the associated shops. 5500 sqft. Yup, the go big before you die approach. But, I still ended up spending >$40K (2000 dollars) on engineering to get the dust systems right. This stuff doesn’t scale from the 2 car garage shop (which is what I had for 25 years). With the advent of the mega-shop builds that KZfaq seems to suggest, people need to invest in experts. Or just try and self-insure your fire risk •••

The man's wearing flannel. He knows what's up, im definitely watching this entire video lol. Thanks for the info very helpful

Thanks for the science lesson, well done. Best explanation I’ve seen so far… and there’s lots on you tube. This alone earned my sub.

Awesome man thankyou so much

Clear and concise - thank you. Great fundamental information.

The Bill Nye of woodworking.

Fantastic video and description of air handling! Learned a bit and increased my overall understanding. Thanks for posting this video. Great stuff

This is a ruddy brilliant video. I feel I much better understand what I'm up against. Dust collection has been a bit of a thorn (or perhaps a splinter) in my side as I try and figure out all the fittings and hoses and layout. This adds another layer of complexity, but a whole lot of understanding. Thank you!

Excellent tutorial. Thanks for the information. I’m setting up a shop and this has been very helpful. 👍👍🇨🇦

Great video. Gonna help me get control of my dust. By the way, since this is a video on dust, those blinds could use a good dusting.

This is amazing, It answered so many questions.

Köszi, "Sanyi bácsi", for the explanatory video, this was just the topic that I needed to start with a second hand shop vac I just got from a friend! I got stalled in the first 2 seconds by the map on your wall, but it made me instantly google the author! Keep up the good work!

Excellent vid. Many thanks, from New Zealand

I think this video gives a great foundational understanding of dust collection, but I feel the need to clarify some things you said about the duct or hose size. Air velocity is absolutely relevant when it comes to friction inside the ducting or hose, but only air volume matters for capturing dust before it escapes the localized partial vacuum near the dust collection intake. I think the example of blowing through a straw is misleading because it may leave people with the false understanding that the increased velocity inside a smaller tube will capture more dust. Keep in mind that suction is all about the difference in air pressure, and suction does not have velocity. When you blow air through a straw, it can move more sawdust because the fast moving air will come into contact with more still air, and cause a greater volume of air to move as it trades velocity for volume. The same does not happen with suction. For any fan that can move a certain volume of air, the dust that is pushed into the vacuum from room pressure will be the same regardless of the hose size, if you aren't accounting for friction. When we account for friction, the bigger hose will perform better. Your example with the shopvac using a larger 4" hose attached is misleading because even though the velocity in the hose is indeed lower and you are seeing fewer chips sucked in, these are not related. The reason fewer chips are sucked in is the same thing that happens inside a vent hood or any dust collector attachment. Your demonstration with the larger tube sucking in fewer chips is a result of it drawing in more surrounding air and less air containing dust, which isn't a factor when your hose is connected to a tool's duct collection port or a vacuum attachment. What happens in the duct or tube after intake doesn't matter (except for losses due to friction or blockage). What matters is the volume of air you are moving into the tube, and efficiency is primarily dictated by the hood's ability to draw more air containing dust than surrounding air without dust. To summarize what I'm trying to clarify, your fan's CFM rating matters a lot more than hose or duct size, and a bigger hose is always better when connected to the same tool or vacuum hood. But you were spot on with all the talk about losses due to friction and general recommendation to use at little flex tubing as possible.

Thanks! This was an outstanding presentation.

thank you

The people that are building dust collection systems using Shop vac's and 2" PVC ducting with all kinds of 90's and T's really need to see this video!. Especially when they are hooking up to equipment that have a 4" dust ports on them. Most woodworking equipment have rated or recommended CFM requirements. Most if not all shop vacs will never meet this requirement especially after all of the pipe, 90's and T's are in place. For the price of a good shop vac, the dust system you are using can be had and would far better be suited for almost any basic DIY'er wood working tool.

Most helpful video in understanding dust collection. Thanks

Great video! Thanks for posting!!

Thank you for coprehensive coverage of the subject! Even i understood most of it 😀

Wow! Really helpful information. Looks like I’ll need to watch it another time or two before really it sinks in, though. I was kind of left scratching my head at the end of it - wondering how to solve this problem on a budget. Or better yet… if it’s even solvable on a budget. Too helpful a video not to subscribe!

Great video, thank you!

Brilliant and timely. Many thanks from Ottawa, Canada.

very inspiring explanation

Thanks, this was indeed super helpful.

very detailed and helpful...thanx

Thank you kindly for the extraordinarily simple explanation.

I read the last edition of Woodshop Dust Control and learned a lot about, well, a lot. I really appreciate how you covered so many facets of woodshop dust and shavings and ways we can protect ourselves and our woodworking environments. I struggled with some of the concepts, though, and found this video to be very good at explaining the factors into overall dust collection airflow. I hope that you plan to release more videos related to dust control, including various equipment, differences between a large collector vs a shop vac, air filtration systems, and personal protective equipment (PPE). Also, I often wonder how much misinformation is out here on KZfaq and on the Internet, so perhaps also clear up some of the confusion if/when you release videos. Also, do you plan on updating Woodshop Dust Control? The copy I read was from the library, and I'm interested in buying a copy for reference. Thanks for the information!

Your book is a classic.

Great video! Thank you so much for taking the time to help educate us novice woodworkers! Do you have any videos that explain how to handle static electricity in your dust collection system? I just purchased a desktop CNC and the static from my shop vac is driving me crazy!

Wish you would have done the readings on the shop vac

Very great explanation. Thanks.

Kedves Sándor! Nagyon jó videó lett, köszönjük szépen!

Great video! Beat dust collection video I have seen!

Thank you for such a great video. Your explanation helped me a lot.

Great video with a simple explanation of the principles. You might want to add along with friction comes static electricity and you need to add a grounding System.

Excellent video, thank you so much.

had to replay the first 2 seconds over and over so i could figure out this guys name. Conclusion? No idea, but it's the best name ever, haha! Great info!!

Extremely helpful. Thanks

great video!

As a Student in a Prof. Bachelor WoodTechnology I can really say this a fantastic way to explain the basics of dust collection. Great Work!

very good video, informative and very well presented, thanks for posting from Garry in the UK

Howdy Sandor!!! I just happened upon this video when I was wanting to build my own cyclone bucket! It was good to see you at the beach in S.C. last year!!! Pamela

Wow!! I wish I could tell you how many people in Facebook groups for hobby level CNC router's and general woodworking group that I have preached dust collection principles to. 100% of my knowledge came from your book. I am designing my 2nd dust collection system right now and I have to say THANK YOU because your book taught me so much.

Very good video in explaining the fluid dynamics of air handling. I was very interested in the changes of volume and airspeed between a 4" and a 2" hose. so many of my tools have 2" ports and I'm currently installing 30 feet of 4" PVC piping with three sanitary T's and blast gates unto a WEN 1.5 HP cyclone dust collector 650 CFM. All turns will have two 45 deg together reducing friction with a total of 4 bends. All will be reduced to a 2" hose to connect to each machine. I'm now wondering if I'm making a big costly mistake? I guess I'll find out once it's all installed.

5:01: Nope Given the same *volume*, the air flowing through a narrow hose will naturally travel at a higher speed than through a wider hose. Volume however wasn't the constraint stated by the presenter, but rather *pressure*. All other things being equal, with the same pressure, the speed will be the same in both hoses. But let's be clear -- the same dust collector, powered by the same motor at the same electrical input won't be exerting the same (negative) pressure on the wider hose and thus the air velocity will be lower. That's the point to remember. The reason the air comes out of the straw at a higher velocity is that a human can't generate the same high pressure in the wider tube -- you're off the human 'pump curve'. Fluid dynamics are lovely, but not always lending to simply explanations.

Thanks a lot for your information, really important. Can you speak about the "gates" in a dust colector system?

Thanks needing info great video

Soooo, what to use?

Excellent content, just what I was out looking for, thanks a lot 🙏👍👍

Answered my questions. To move large quantities go fo 4” pipe, smaller quantities go for 2.25”. (Bigger pipe requires bigger everything) and don’t bother with a 40’ hose unless you have a lot of power.

Nice to see Sandor still in the woodworking business and still teaching us in a way that we can understand and apply to our shops.

I have a Rockler Dust Right 650. It has a 4 “ inch hose. My Tools Dewalt 7845 Table Saw has a 2.5 inch dust port. I also have a Ryobi 12” inch Miter Saw with 1.25 inch dust port. I’m new to Woodworking and trying to figure out the best way to set up dust collection. I would like to run a Y fitting from the DC. So I could run a 4 inch hose with 2.5 inch reducer for the Table Saw and a 4 inch hose with a 1.25 inch reducer to the Miter Saw. But I know if it will work right

Watched to the end. Walked away with the notion that I need a 3 phase 25 Hp system with 10 inch metal or plastic pipes. A follow up video is needed to move from the abstract / theoretical to the concrete / real world application.

What cfm machine are you using for the demonstration

Very simple explanation..thanks..

Now that you’re done testing, I’ll take the PM off your hands. Lol. Good vid.

do they make smooth wall flex hose?

Every time a popular topic 👍🏼

Hi, i saw your video and I have a question to ask about the dust collection system that i'll be bulding for my very small bedroom shop. I want no costly mistakes. Ok, my Shop-Vac is a 6.5HP with a 2 1/2" hose attachment. Now here's my question. Should I stick to the 2 1/2" piping or should I use larger PVC pipping like 3 or 4"? Will the larger hose give me more suction towards chips and dust, or it would be the exact same as if I would use a 2 1/2" pipping? And 2nd question. I know that flexible hose is not a good idea, cause the ridges cause loss of suction. But I still need to ask. If I'd use flexible hose, BUT at the exact length between each connectors, no bending of it, fairly tight fit, would the loss of suction still be the same issue, cause of the ridges? Or it could do the job? OR should I stick to PVC? Please let me know. I'd greatly appreciate your help. Thanks

How do you address the static electricity build up? Some forks wrap a copper wire to a grown source

I bought the harbor freight 2hp dust collector which is a 4” inlet. I want to add a Oneida super duty dust collector and make a 2 stage. They offer 4”,5”,&6” sized super dust deputies. How do I do the math to know which is the most efficient????

Ribs of the flex hose are causing turbulence which creates significantly more resistance to the air flow than surface friction.

I think I am getting the idea. So the more air you can move the better. Thanks for breaking down the physics much appreciated. I am going to put my above 150 IQ on this and dust free my shop.

Thanks a lot.

Thanks for sharing that

Very good information. Please mention in another video if possible, the static electricity generated by the dust and how to deal with it. Thanks a lot.

...and? What do I use then? This video doesn't really give any answers. If one ignores the complexity of the system - and is limited to the same dust collector (not knowing its performance): Is it better to have a long wide internally smooth hose - or a long narrow internally smooth hose? Also, what about combination of hose diameters? Is it better to run a wide duct-work, the narrow them down as the duct gets longer?

how much noise can i stand to get the job done?

8:52 DORA THE EXPLORER MIXED-UP SEASONS

What unit works best with low decibel levels?

Hello, I was hoping someone could help me with an issue I'm having with my 4inch dust collector. Is anyone available?

Not to mention the static electricity caused as the air flows through any convayence.

Can you run ductwork under a raised floor? Then up to the cyclone? Most setups I've seen are overhead.

Ironic that you can see dust all over the venetian blinds behind him. Clearly his dust collection is not trapping the fine particles.

Why doesnt anyone combine vacuum plus blowing to make a semi closed system? Because it doesnt help?

A very clear way of explaining this! Im interested in the pros and cons of mixing different diameters. Is it best to stick with one at all times? I bought a "shop vac" (not the brand though) and it has a 32mm diameter. Is there any point in using a larger diameter for a longer path? (when the machine is in the other end of the shop for instance).

So, what your saying is 4" is bigger than 2"?

I have the Harbor Freight system with 4” PVC. All machines in a row (split the two car garage in half) Air flow is ok but it’s hooked up with 120 service. What’s the benefit of upping to 220?

Does anyone else see the dust collecting on his window blinds?

what causes pressure losses?

I'm not trying to be funny..but does anybody else think he sounds like Brent spiner?..

I used to sell large dust collector and you should ground (connect to the ground not the negative in a panel box or a ground rod put in the earth) the duct work as the dust moves through creates static electricity which has been known to cause fires.

duuuuuuuuuuuuude

My friend, this is an amazing video, however I must inform you of something. AT TIMES YOU SOUND EXACTLY LIKE BRENT SPINER?! Everyone close your eyes and imagine Commander Data speaking. It's uncanny.

dear god, the size of rthat powermatic unit is absurd!

a complete lack of conclusion????

If only I could spell your name, I could find your book.

Even going from 3” to 4” you nearly double the volume.

Unless you get a whole room that is a vacuum chamber you will never solve miter saw dust collection

Anyone who can't figure out that a 4" hose can carry 4x the volume of a 2" hose (or more given friction considerations) didn't get much out of this video.

I assume this sort and level of explanation is aimed at Americans. They seem to need everything aimed at 5 years old children.

This is more has to do with fluid dynamics than woodworking 😅