Dust Col. Adapters: what works? 4" to 2-1/4 OD or 2-1/4 OD

Just got my dust collection 6" (sewer) PVC run done, have blast gates coming off the PVC 6" x 4" "wye" connections, and 4" flex hoses out to each tool. The next part I thought would be easy, but I don't want to order the wrong adapters.

Seems like none of the adapters I have found mention both the ID and the OD of the small end to go to the tools. I have 3 tools that have the same size dust collection ports (14" Ridgid bandsaw, 12" Delta disk sander, and oscillating sander from Ridgid) - they all have exactly 2-1/4" ID on all the ports, and are all approximately 2-1/2" OD.

The small hose that came with the Delta has 2-1/4" OD ends and fits perfectly in all 3 tools.

My first thought is that I want adapters as large as possible, to keep the air flow high. To me, that would mean using 2-1/2" ID adapters, and slipping them over my tool's ports. Am I thinking about that correctly, or does it really not matter?

All of the adapters I have found just say 4" to 2-1/2", or 4" to 2-1/4". They never say whether the size they are listing is the ID or the OD of the adapter, so I have to assume it is the OD they list.

Actually, the only 4" adapters I have found with a 2-1/4" OD end are the funky offset adapters, and long funnels (that require extra room on the benchtop.) Maybe that's all there is, but that offset design seems inefficient, and the long funnel, while fine for my bandsaw, will be a bit long for the benchtop sanders.

Here are the ones I found:
Offset reducer: http://www.woodcraft.com/Product/200...r-Fitting.aspx

Long funnel: http://www.woodcraft.com/Product/202...-4-x-2-14.aspx

I have seen nothing listed with a 2-1/2" ID (I have to assume all the 2-1/2" adapters list the OD.)

What works, and where do I get 'em?

Thanks,

Dennis

Quote:

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Originally Posted by Dennis Leahy

Just got my dust collection 6" (sewer) PVC run done, have blast gates coming off the PVC 6" x 4" "wye" connections, and 4" flex hoses out to each tool. The next part I thought would be easy, but I don't want to order the wrong adapters.

Seems like none of the adapters I have found mention both the ID and the OD of the small end to go to the tools. I have 3 tools that have the same size dust collection ports (14" Ridgid bandsaw, 12" Delta disk sander, and oscillating sander from Ridgid) - they all have exactly 2-1/4" ID on all the ports, and are all approximately 2-1/2" OD.

The small hose that came with the Delta has 2-1/4" OD ends and fits perfectly in all 3 tools.

My first thought is that I want adapters as large as possible, to keep the air flow high. To me, that would mean using 2-1/2" ID adapters, and slipping them over my tool's ports. Am I thinking about that correctly, or does it really not matter?

All of the adapters I have found just say 4" to 2-1/2", or 4" to 2-1/4". They never say whether the size they are listing is the ID or the OD of the adapter, so I have to assume it is the OD they list.

Actually, the only 4" adapters I have found with a 2-1/4" OD end are the funky offset adapters, and long funnels (that require extra room on the benchtop.) Maybe that's all there is, but that offset design seems inefficient, and the long funnel, while fine for my bandsaw, will be a bit long for the benchtop sanders.

Here are the ones I found:
Offset reducer: http://www.woodcraft.com/Product/200...r-Fitting.aspx

Long funnel: http://www.woodcraft.com/Product/202...-4-x-2-14.aspx

I have seen nothing listed with a 2-1/2" ID (I have to assume all the 2-1/2" adapters list the OD.)

What works, and where do I get 'em?

Thanks,

Dennis

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Sorry, I don't have a better analogy, but you are trying to pick apples with and orange picker. There has been some recent posts here or on SMC about it. A DC is designed to move large volumes of air and to do so requires large ducts, large ports, etc. If possible, and supported by the performance of your DC's fan, you should be running 6" duct from the DC to the machine, no reduction to 4" and certainly no reduction to anything smaller. Enlarge the DC port on the machine if necessary. Necking down to a 2-1/2" or 2-1/4" port defeats the operation of a DC. If you can't enlarge the port on the machine/tool build a shroud, and if you can't do that use a shopvac which has higher static pressure and can draw air much more easily through 2-1/2" etc. ducting and ports.

Thanks for the reply, Alan. I can see some possibility of tearing into the bandsaw lower door and installing a larger port, but not on a Delta 12" disk sander or the Ridgid oscillating sander. I know that larger woodworking equipment has larger ports, but these smaller tools just do not offer them.

Looks like I failed industrial engineering 101, because I have a 6-inch main, and 4-inch "wye" drops/connections off the main. I know larger ducting is better for removing small particles, and I know that cyclones are about the only way to really do it right. However, it was very difficult to come up with the $1000 I just put into the purchase of a Grizzly G0548Z (http://grizzly.com/products/2HP-Cani...llector/G0548Z) dust collector and all the ducting, hose, and fittings. Coming up with $2500 to $3000 to really do it right was simply beyond my means - now or in the foreseeable future. Buying new tools with bigger ports is also something I just cannot afford. Plus, in my tiny (13x20) one-room basement guitarmaking shop, it is about all there is room for.

I don't mean to kill the messenger. I'll look into shrouds, and plan on getting an air cleaner unit for the inevitable particles that my system can't remove. I do appreciate that you took time to post, even if it was not what I wanted to hear. But what we want to hear and reality sometimes are not the same.

Dennis

Quote:

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Originally Posted by Dennis Leahy

Thanks for the reply, Alan. I can see some possibility of tearing into the bandsaw lower door and installing a larger port, but not on a Delta 12" disk sander or the Ridgid oscillating sander. I know that larger woodworking equipment has larger ports, but these smaller tools just do not offer them.

Looks like I failed industrial engineering 101, because I have a 6-inch main, and 4-inch "wye" drops/connections off the main. I know larger ducting is better for removing small particles, and I know that cyclones are about the only way to really do it right. However, it was very difficult to come up with the $1000 I just put into the purchase of a Grizzly G0548Z (http://grizzly.com/products/2HP-Cani...llector/G0548Z) dust collector and all the ducting, hose, and fittings. Coming up with $2500 to $3000 to really do it right was simply beyond my means - now or in the foreseeable future. Buying new tools with bigger ports is also something I just cannot afford. Plus, in my tiny (13x20) one-room basement guitarmaking shop, it is about all there is room for.

I don't mean to kill the messenger. I'll look into shrouds, and plan on getting an air cleaner unit for the inevitable particles that my system can't remove. I do appreciate that you took time to post, even if it was not what I wanted to hear. But what we want to hear and reality sometimes are not the same.

Dennis

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My first shop was smaller than yours but I shoe-horned in DC piping though I put the DC outside. If you are willing to do a little work and scrounging you don't need to spend that kind of money. I did not have big bucks then either (still don't!). I bought an old 3hp Grizzly DC from a lumber yard that went out of business for slightly more than $200. I stripped it down to motor and blower. I used about $50 in sheet metal and misc parts to make a cyclone. My 10' X 10' shop:

http://www.ncwoodworker.net/pp/data/...um/Shop_21.JPG

Even after buying new, top quality 300 sq. ft. cartridge filters, I still had less than $500 into my cyclone. Add PVC S&D (ASTM 2729) ducting for my new 25 x 40" shop and shopmade blast gates, I had a top of the line system for under $1000 total cost!

http://www.ncwoodworker.net/pp/data/.../P10100382.JPG

http://www.ncwoodworker.net/pp/data/.../P10100382.JPG

I have no major problem with cutting new dust ports into machines, but only if there is no other way. I didn't want to cut a big hole in my bandsaw door so I made a removable shroud that slides under the bandsaw and connects to 6" ductwork, yet still allows the table to tilt. Here is pic of my first version. The current one is much simpler.

http://www.ncwoodworker.net/pp/data/...m/PB130004.JPG

I'm not sure which Delta sander you have. I have the old floor model 12"disc/6"X48" belt sanding station. I split the 6"DC hose into two 4" one goes to the disc pickup, the other to the belt.

http://www.ncwoodworker.net/pp/data/...um/Sander8.JPG

You are on your own with the Rigid. But small tools (routers, ROS, biscuit jointers, etc.) should be serviced by a shopvac not a DC. Here are some pics of my shopvac setup:

http://www.ncwoodworker.net/pp/data/...m/PB050004.JPG

http://www.ncwoodworker.net/pp/data/.../PB0500161.JPG

http://www.ncwoodworker.net/pp/data/...m/PB050006.JPG

Alan,

Thanks for the additional info and photos. Wish I had consulted with you before I did my DC setup, but I'm stuck with what i just finished - for now, at least.

My Delta 12" disk sander is the 31-120, and I see no way to enlarge the port. Same with the Ridgid OSS - no way to enlarge the port (though I can certainly improve the dust extraction by additionally collecting dust above the table, with a shroud.

I like the idea of the mini-Clearvue cyclone with a ShopVac as a small dust collector, and especially like the idea of that high-pitched whining thing being stuffed in a cabinet.

Excellent idea with the shroud for your bandsaw! Looking at my bandsaw, I see that I can do the same thing (although it would be with a 4" port - though that should be a tremendous improvement over the 2-1/4" port which actually then funnels down to a 1-3/4" x 5/8" rectangular opening near the blade path. Geez! No wonder even with a completely clean filter on a ShopVac it is impossible to capture all the dust!) Thank you, I should be able to improve upon that greatly.

I am planning to build a drum sander (6" x 18" drum, with powered infeed and outfeed rollers), and the DC was a critical piece of equipment that simply had to be there for me to consider drum sanding in my little shop. Most of the units on the market that hobby luthiers have in their shops (such as the Performax/Jet 16-32) have a single 4" port, and most users report that with a dust collector like mine and 4" flex hose, they are able to collect most of the dust. (I know that the finest - and most dangerous - submicron particles cannot be seen unless they are in high density, so some of these guys may be mis-reporting just how much dust they are collecting.) I had thought that I would include a pair of 4" ports on my unit's shroud, plus use a "barrier" of bristles (from a cut apart broom) at infeed and outfeed to sort of 'corral' the dust better than typical commercial units do, giving the DC a bit longer to catch and remove more particles. A typical job for a drum sander in a luthier shop is sanding wide panels less than 1/8" thick, so I think the bristles can easily make contact with the bed and provide a bit better suction for the ports above.

Thanks again, you're helping me see possibilities for inexpensively improving what I currently have.

Dennis

Quote:

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Originally Posted by Alan Schaffter

... If possible, and supported by the performance of your DC's fan, you should be running 6" duct from the DC to the machine, no reduction to 4" and certainly no reduction to anything smaller. Enlarge the DC port on the machine if necessary. Necking down to a 2-1/2" or 2-1/4" port defeats the operation of a DC. If you can't enlarge the port on the machine/tool build a shroud, and if you can't do that use a shopvac which has higher static pressure and can draw air much more easily through 2-1/2" etc. ducting and ports.

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It's very commonplace in professionally-designed duct systems to reduce to 4" ports and the system will work quite well. You can see my system on my website. The design was done mostly by Oneida engineers.

I agree, in part, with the use of a shop vac for 2-1/2" ports. I have only one port of that size and it's for my router table fence. I have an undertable containment box with a 4" port and the 2-1/2" line wyes off of it. I have a separate blast gate on the 2-1/2" port and only open it when I'm using the fence with a DC port. With both the 4" and 2-1/2" gates open, I get excellent collection.

Quote:

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Originally Posted by Bill Arnold

It's very commonplace in professionally-designed duct systems to reduce to 4" ports and the system will work quite well. You can see my system on my website. The design was done mostly by Oneida engineers.

I agree, in part, with the use of a shop vac for 2-1/2" ports. I have only one port of that size and it's for my router table fence. I have an undertable containment box with a 4" port and the 2-1/2" line wyes off of it. I have a separate blast gate on the 2-1/2" port and only open it when I'm using the fence with a DC port. With both the 4" and 2-1/2" gates open, I get excellent collection.

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Bill, "it's very commonplace in professionally-designed duct systems to reduce to 4" ports" but in most home systems it is absolutely not necessary and actually reduces the performance of those systems.

The reason Oneida and others do it with dust collection systems and also why HVAC system designers reduce the size of the duct (check it out in the nearest open ceiling restaurant with rounc ductting), is because they have multiple openings (ports, registers, etc.). Reducing the diameter of the drops has two purposes- it balances the system between drops and helps maintain sufficient velocity so the dust and chips stay in suspension if more than one drop and its blast gate are open.

If you have a typical home shop and are a typical woodworking you use only one machine at a time. If you reduce the diameter of your drops (and ports) you must realize you are sacrificing performance, big time. With the same blower, the CFM possible through a 4" duct is considerably less than that through 6" duct as many people who originally ran 4" ducting have found. For collection from one machine at a time it is best to run as large a duct, as far as possible, without reducing at a drop or port. The object is to collect as much dust as possible at the source. Again, this is for a home shop not a commercial one where ductwork runs long distances and supports multiple machines running at the same time.

Dennis,

A couple of things about collecting dust from any machine- use as large a pickup, blast gate and ductwork as the DC will support . . . AND ensure there is a source of take-up air. Too many folks shroud their machines (tablesaw is typical offender) too tightly, but provide no source of takeup air. Doing that is no different than having a small port or ductwork.

Sounds like you are foregoing a commercial Performax type maching for a home-built one. I've heard a lot of luthiers go with manual feed, table-top units like the Sand Flee.

I do A LOT OF TINKERING (check out this link) but decided against building a drum sander. I bought an old 24" Grizzly dual drum machine and started tweaking- I'm not done. I changed the insufficient dust ports (one 6" is better than two 4" see pic below), I swapped out the single speed AC conveyor motor with Baldor DC gear motor and added a controller so I could vary the feed rate. I plan to do some additional major work - like you I plan to add a brush on the outfeed, however I plan to add a rotating to sweep the dust back in where it has a second chance of being picked up. Lastly I plan to re-design the drum bearing mounts so that I can select the front, back, or both drums- if you need to make multiple passes, you are wasting the second drum if you have different grits on the front and back.

Here is a pic of my drum sander and some DC ducting taken before I closed in the knee wall.
http://www.ncwoodworker.net/pp/data/.../P1010088a.JPG

Quote:

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Originally Posted by Alan Schaffter

Bill, "it's very commonplace in professionally-designed duct systems to reduce to 4" ports" but in most home systems it is absolutely not necessary and actually reduces the performance of those systems.
...
If you have a typical home shop and are a typical woodworking you use only one machine at a time. If you reduce the diameter of your drops (and ports) you must realize you are sacrificing performance, big time. ...

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Alan,

I'm sure you mean well. The engineers at Oneida got all the information about my home shop and tools, then designed a layout that works great. It works fine whether I have one 4" gate open and supports having two or three open as necessary as well.

What are your credentials?

Quote:

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Originally Posted by Bill Arnold

Alan,

I'm sure you mean well. The engineers at Oneida got all the information about my home shop and tools, then designed a layout that works great. It works fine whether I have one 4" gate open and supports having two or three open as necessary as well.

What are your credentials?

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"Mean well", I'm just trying to provide the facts.

The "engineers" or a customer support guy probably just plugged the numbers into a spreadsheet- it is not rocket science but it is physics and math (both of which I have an extensive background). The point is, based on the fan curve of your system and other factors (cyclone, filters, etc.)- your system might be balanced, so it seems to work "fine" whether you have one or more 4" gates open. "Fine" is a relative, ill defined term- have you computed or measured the flow a each drop using a Magnehelic manometer and pitot tube or some other method with one, two, or three gates open? Have you measured the ambient dust around your machines with a Nylos or other particulate meter? If not, "fine" means nothing.

Finally, as long as the air velocity does not drop below the generally recommended minimum of 4000 FPM, do you dispute you would have better collection from a 6" drop than a 4" drop and in your system if only one gate was open and plumbed all the way to the tool with 6", 7" or whatever the diameter of the blower inlet?

If you doubt it, I suggest you read Bill Pentz's site or even Sandor Nagyszalanczy's, Woodshop Dust Control (Taunton 2002)

Dust collection is like money- you can never have too much!

Delta makes an adapter for your disk sander. I recently bought one at Klingspor's Woodworking Shop. It cost about $10

Quote:

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Originally Posted by Bruce Wrenn

Delta makes an adapter for your disk sander. I recently bought one at Klingspor's Woodworking Shop. It cost about $10

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Thanks, Bruce. This one?: 4" to 2-1/4" adapter (I've ordered a couple of these, because it was all I could find.)

Or do you mean some sort of replacement shroud with a 4" port? That would be better. If I was convinced it would make an incredible difference, I suppose I could entertain the notion of making a new shroud with a 4" port. I pulled the existing shroud off, and see the 2-1/2" OD is partially cast into the metal casting. Still, it could be done, but it would be yet another project that keeps me from my projects.

Alan and Bill, thanks for the input. I spent enough time on Bill Penz's site to make my head swim, and I'm convinced he is 100% sincere and was probably one of the very first people to provide the straight scoop on dust collection, and especially on the sub-micron particles. He actually changed (part of) the industry. So when I say I REALLY wanted a full on ClearVue with a 5hp motor and 16" impellor, and 8" ducting throughout my shop... well, believe me, I know what I am doing pales in comparison. I simply do not have the extra $2000 to buy the ultimate system, and so I'm trying to get the best bang for the buck out of my $990 (my real total cost), and cannot afford to significantly change my system for the foreseeable future. Guitarmaking, even at the hobby level, "requires" lots of specialty tools (oh sure, someone can build guitars with a Swiss Army knife, but I don't want to), and the cost of the specialty tools and the exotic wood is all I can handle financially. The other reality is that I have hobbyist power tools. I have worked as a cabinetmaker and architectural millworker in shops with "real" woodworking tools (like a $15,000 beam saw, or a $4000 shaper, or a $3000 jointer), and these hobby-level tools are just not ported for 6" or larger openings. Like the prison guard said in Cool Hand Luke, "man's got to know his limitations", and I do realize I'm getting set up to collect some of the dust, not all of it.

Alan, I have designed a drum sander, and have collected parts to build it, so at this point, even if I found a $400 Performax 16-32 on Craigs List I would not buy it. I have a number of luthier friends that have built one, and they all do at least an adequate job. The best of the home built machines may be uglier but may be more accurate than a $1200 sander. Again, if this was a commercial cabinet and furniture shop, it would be a different story, but I'm confident I can build a unit that will meet my needs. One question would be whether two 4" ports connected to my drum sander's shroud will collect more dust than a single 4" port. Connecting two 4" flex hoses means opening up two blast gates simultaneously, so is the drop at each hose so great that a single 4" would actually do better at extracting the finest particles (that my system will extract.)

Sorry, this is long-winded. I'll stop here and say thanks.

Dennis

Quote:

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Originally Posted by Alan Schaffter

... I'm just trying to provide the facts.
...

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The facts in this case are that a vendor that designs and builds excellent DC systems provides shop design support to customers. They probably do have a spreadsheet or other design aids into which they can input the type of tool and distance to determine the requirement for that location. Why on earth should they have to sit there with a slide rule and re-invent the wheel every time they need to design a layout??? :confused:

Whether you can accept it or not, the 4" ports in my system allow enough air flow to suck up everything in site, including small animals. Example: I have two floor sweeps with 4" duct running to them. These are mounted at floor level, therefore the term "floor sweep". The 4" duct goes straight up the wall about 8.5' to a wye into the 6" main. There's a blast gate about half way up the wall. Anything within several inches of the sweep gets sucked into the system instantly. :eek:

I'd rather spend my time making sawdust and my money on woodworking tools than acquire the instruments to make measurements that do nothing more than second-guess a professional organization. I might be anal but I'm not that anal. ;)

Quote:

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Originally Posted by Dennis Leahy

One question would be whether two 4" ports connected to my drum sander's shroud will collect more dust than a single 4" port. Connecting two 4" flex hoses means opening up two blast gates simultaneously, so is the drop at each hose so great that a single 4" would actually do better at extracting the finest particles (that my system will extract.)

Sorry, this is long-winded. I'll stop here and say thanks.

Dennis

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Two ports of equal size will generally collect more than a single of the same size- if they are connected to a larger duct. i.e. two 4" into a 6" vs one 4" into a 6". But even better, since you have a 6" main, run it all the way to the machine and build the sander cover with a single 6" port. Not only does 6" have a larger cross section which can move more air it has less interior surface area and less resistance (circumference, pi x D (times length) than two 4" pipes, i.e. 6 pi < 2 x 4 x pi. Duct cross section and interior surface area both affect flow. Even if you had two ducts with the same total cross section as a larger single one, the single duct is better. Plus you are eliminating a wye fitting- EVERY fitting adds resistance and takes its toll on flow, so the fewer fittings the better. I don't remember the exact numbers, you can probably find them on Bill Pentz's site, but I believe one 4" wye adds the equivalent resistance (affects static pressure) the same as adding 6 more feet of duct.

When a lot of people think of dust collection, they think of a neat shop devoid of chips and visible dust, when the most important dust to collect is invisible- if you collect that, you will likely also collect the other. The reverse is NOT true, however. Though a particular DC may remove most of the dust and chips from inside a machine, it may not be collecting the fine invisible dust that always escapes and floats in the air, often for hours or more!!! So you need to collect air in the vicinity of the machine too. Or just wear a good mask.

I know a lot of this sounds like fear mongering, but it is the truth. Don't yell this out loud since it has significant impact on the entire woodworking industry and hobby, but NIOSH has declared chronic exposure to wood dust to be a carcinogen. Granted, a lot of factors are involved- dust densities, length and frequency of exposure, species, personal sensitivities, etc. etc. etc. but it is a fact. This wasn't much of a problem before Norm, NYW, TOH, etc. because few hobby woodworkers had many fine dust generating power tools in their shops. Few had more than a tablesaw and worked mostly with hand tools. Heck, a lot of cabinet shops didn't have what some hobby woodworking shops have today. Some tools weren't even invented yet, like random orbit hand sanders which combined with drum sanders, etc. generate tons of fine dust.

I'll get off my soap box now. You don't need to spend lots of money, though it sure makes it easier. I frankly don't have the money for a ClearVue, but I do have a certain level of ability to design and build stuff inexpensively (am not afraid to attempt to build anything) and am good at scrounging.

Quote:

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Originally Posted by Bill Arnold

The facts in this case are that a vendor that designs and builds excellent DC systems provides shop design support to customers. They probably do have a spreadsheet or other design aids into which they can input the type of tool and distance to determine the requirement for that location. Why on earth should they have to sit there with a slide rule and re-invent the wheel every time they need to design a layout??? :confused:

Whether you can accept it or not, the 4" ports in my system allow enough air flow to suck up everything in site, including small animals. Example: I have two floor sweeps with 4" duct running to them. These are mounted at floor level, therefore the term "floor sweep". The 4" duct goes straight up the wall about 8.5' to a wye into the 6" main. There's a blast gate about half way up the wall. Anything within several inches of the sweep gets sucked into the system instantly. :eek:

I'd rather spend my time making sawdust and my money on woodworking tools than acquire the instruments to make measurements that do nothing more than second-guess a professional organization. I might be anal but I'm not that anal. ;)

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Bill, you are missing two points. First without testing you don't know if you are getting the suction (CFM, not SP) you need to adequately capture as much fine dust as possible at the source- in AND AROUND the machine(s). Just because Oneida says so it doesn't make it so- any differences between the execution of your ducting and their "design" will affect performance. Suction (SP) to pick up "small animals" or a bowling ball (like one of the vacuum commercials), is NOT the same as suction (CFM) needed to capture fine dust at the source. Your system may do that as well, but we don't know. If I were Oneida, I would over-build or over-spec a system- with DC's, bigger is ALWAYS better.

Secondly, you must ask yourself if you have a single person, home woodshop and since it is an irrefutable physics fact that air flow (CFM) is higher through a 6" duct than a 4" duct, why are your drops 4"? Is it because 4" is cheaper (true), is it because you told them you would, or might be using more than one tool at a time (so they designed for this option), is it because you have an unusual layout with high SP losses and need to reduce to maintain the minimum 4000 FPM, or is/are there some other reason(s)?

One thing for sure, it is not because 4" allows higher CFM than 6". Ideally, you want to use the largest duct possible (for max CFM) everywhere, as long as your blower and its fan curve will maintain 4000 FPM.

In my case, having just completed the PVC run, I will not be making any changes immediately. If there was a way to cut out a 6" x 4" wye, and replace it with a 6"x 6" wye, and run a 6" flex hose for the (future) drum sander, I would do it. However, since my shop is so small, I literally have back-to-back-to-back fittings. To go up the wall where the dust collector sits, across one wall (under a window) up to the ceiling (abutting a soffit covering the house's HVAC ducting), and then take a 90° turn down the other wall, I have a 45°, 45°, wye, wye, 45°, 45°, 45°, 45°, wye all connected with just enough 6" sewer pipe to glue them together. I can't remove and replace any one piece, so I literally would have to start over with the PVC to get 6" wyes in-place. The cost difference would really only have been in purchasing 6" flex hose down to the machines, and probably some adapters to drop from 6" to the machine port sizes. So, like I said, I'm a bit pissed off that I didn't spend more time on Penz's site or ask a few more questions. Then again, I wonder if the Grizzly G0548Z, with its supposed 1700CFM max and 10" static pressure max would really have moved enough air once the 1 micron filter canister was micro-clogged with real-world dust. If that unit, at its "doable" price point, is honestly not up to the task, then once again, I would be stuck collecting most of the dust and only a percentage of the finest particles.

I think what Bill is trying to tell me is that I won't see any dust. I think what Alan is trying to say is to underscore Bill Penz's words, and make me realize that I could have done better with larger ducting, and that there will still be invisible dust particles in the air. And, at this point in the life of my wallet, that means either scrounging for a fan, buying a pleated/pocket filter and some pre-filters and build an air cleaner, or start saving up for a commercial air cleaner unit. I wonder if this cheap one at Grizzly is a waste of money: http://www.grizzly.com/products/g5955

Dennis

Quote:

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Originally Posted by Dennis Leahy

... I think what Bill is trying to tell me is that I won't see any dust. I think what Alan is trying to say is to underscore Bill Penz's words, and make me realize that I could have done better with larger ducting, and that there will still be invisible dust particles in the air. ...

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Alan has been quoting Pentz's site almost verbatim - nothing wrong with that. There are good points about what both of them are saying but there's also something to be considered in real life situations. Experiences of other woodworkers in their shops should carry as much or more weight than speaking to the pure engineering aspects of a DC system.

In my case, I get excellent collection from the 4" port at the bottom of my tablesaw cabinet. I've added collection above the blade as well. There is no cloud of dust around the saw. Now, when I ran duct to my tablesaw, I took 6" to a 6-5-4 wye under the bench behind the saw. The 5" side runs to a 5" blast gate only a few inches away from the 4" port on the saw. I did this so that, at some point, I can increase the port size on the saw. That modification has taken a back seat to everything else because I don't have the "cloud of dust" surrounding my saw.

For my miter saw, I have a 5" duct off a wye on the 6" main. It feeds to a 5" blast gate and 5" pipe runs to the bottom of my MS dust containment box. I stayed with 5" in this case because the side of the box is MDF that I could cut out easily. I can tell no difference in dust containment between having the 5" hard duct and a 4" flex that I had run to the containment box originally. When I cut a piece of MDF without the DC on, there's a cloud of very fine dust billowing out of the upper portion of the containment box and drifting around the room. With either the original 4" or the 5" I now have running to the box, the fines are drawn into the box and DC pipe immediately.

My system allows me to have multiple ports on a branch open simultaneously. Quite often, I'll have the MS and TS gates open as I work between them. I see no appreciable reduction in dust control in that situation.

You can see my overall duct system (as approved by Oneida) as well as certain details on my website by clicking on my name above, then clicking into my site.

Just FWIW, the ports you are talking about are shop vac ports. A standard small end of the shop vac will slip into that 2-1/4" ID hole and friction fit.

Reducing from 6" to 4" down to 2.5" is not particularly effective. I've tried it, the results were UGLY...

For the shop vac port equipped machines, either upgrade your ports to 4" at least, or use a shop vac with a separator like a Thien or a Dust Deputy and a HEPA filter...

Dennis,

I hope I didn't read in your post that you glued your PCV duct/fittings together?!?!?!? While it won't hurt operation, you are stuck with your layout and will need to cut it apart and discarding fittings if you make a change. For future reference friction fit is fine and pretty airtight, but if you want to ensure that, apply a SMALL bead of pure SILICONE (not latex) caulk to the OUTSIDE of the joint AFTER it is together. This seals it up tightly, yet allows the fittings to be pulled apart later. You can easily rub your fingers over the silicone to remove it. As much thought and design effort I put into my system I have had to reconfigure portions of it over time- following the above recommendation allowed my to do it easily and reuse most of my materials.

I don't remember who said they had a 4" port on their table saw, but if it is an attached port plate, remove it and make your own. Below is a pic of the 6" port I made for my tablesaw cabinet from MDF and 1/2 of a PVC fitting. It attaches with screws so the only machine mod was to drill two screw holes. Rather than buy a 4" plastic aftermarket port I did something similar to my jointer so it would also have a 6" port. I have an overblade pickup on my TS too.

http://www.ncwoodworker.net/pp/data/...m/P5160021.JPG

6" port on a jointer (also has the prototype of my autogate)

http://www.ncwoodworker.net/pp/data/...m/P2240011.JPG

http://www.ncwoodworker.net/pp/data/...m/PB050010.JPG

http://www.ncwoodworker.net/pp/data/...m/PB050012.JPG

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Originally Posted by Alan Schaffter

... I don't remember who said they had a 4" port on their table saw, but if it is an attached port plate, remove it and make your own. ...

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My Jet tablesaw has a 4" port as do most tablesaws I've seen. On my Jet, there is a 4" flange screwed to the cabinet over a 4" hole. What I had planned to do is remove the 4" flange and cut a rectangular opening to accommodate a straight boot between the blast gate and cabinet. A 5" round to 8"x3.25" boot will fit in the space pretty well. My biggest problem at this point is two-fold: 1) My current arrangement is working and 2) at my age crawling around on the floor under my extension tables isn't all that attractive! :o

One other thing to consider with dust/chip collection on the tablesaw is its internal design. My Jet has a steel plate sitting at an angle from the upper right side of the cabinet to lower left to aid in getting chips to the port. Most of the heavier material slides down the plate but some remains. Adding a steeper plate would help the process - another back burner project! ;)

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Originally Posted by David Hostetler

... Reducing from 6" to 4" down to 2.5" is not particularly effective. I've tried it, the results were UGLY... ...

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Amen! Don't expect "shop vac" performance. I have that setup for my router table fence port and it's OK because of the specific duty. When I use the 2.5" port with a shop vac hose on it, I can pick up the usual dust and chips from the floor, but it's far from being as effective as a shop vac.

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Originally Posted by Bill Arnold

My Jet tablesaw has a 4" port as do most tablesaws I've seen. On my Jet, there is a 4" flange screwed to the cabinet over a 4" hole. What I had planned to do is remove the 4" flange and cut a rectangular opening to accommodate a straight boot between the blast gate and cabinet. A 5" round to 8"x3.25" boot will fit in the space pretty well. My biggest problem at this point is two-fold: 1) My current arrangement is working and 2) at my age crawling around on the floor under my extension tables isn't all that attractive! :o

One other thing to consider with dust/chip collection on the tablesaw is its internal design. My Jet has a steel plate sitting at an angle from the upper right side of the cabinet to lower left to aid in getting chips to the port. Most of the heavier material slides down the plate but some remains. Adding a steeper plate would help the process - another back burner project! ;)

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Your plan sounds good, except I would go for 6" round to rectangular and upgrade the drop from 5" to 6". I know what you mean about getting down and dirty! I finally passed the big Six Oh this year.

Most saw manufacturers, with the possible exception of SawStop have not given a lot of thought to cabinet design. There are so many things they could have easily (and inexpensively) done to improve dust collection- shroud the blade, better internal ramp, bigger ports, take-up air source that blows directly on the blade, etc., etc. The sloping plate in my Unisaw is not steep either though with my flow it works fine and I get no dust build-up, but they didn't seal it to the cabinet sides. Before I automated my DC, if I made a couple of quick cuts without turning on the DC, dust would make it through the cracks and collect on the floor under the saw. Now whenever the saw is on the blast gate is open and the DC running so it is not a problem, but sealing the gaps around the plate was one of the roll-around jobs I kept putting off.

I was really put off by SawStop and their early regulatory efforts, but I must say Dr. Gass and Co. have really put some serious thought into not just the blade safety but dust collection and overall design. Of course, if money were no issue I would have a SawStop and Festools.

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Originally Posted by Alan Schaffter

... I know what you mean about getting down and dirty! I finally passed the big Six Oh this year. ...

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Well, you're just a young whipper-snapper! I got to start carrying my Medicare card this year! ;) I can get down on the floor OK (gravity works great); it's the standing up straight again that gets me! :eek:

Unfortunately, I know what you mean!!!

For the smaller tools you should be fine with the 6-4-2 1/2 reduction. My Dust Ape handles it fine on the oss.
Don't forget about Fernco type couplings, they can solve many DC problems when hooking up to machines.

Dust collection isn't perfect, never has been, never will be. Do the best you can and move on, every system is different, no cure all.

Ed

Good point, Ed.

One of my transitions is from a 4" port to a 2.5" adaptor and gate for my router table fence. I can then plug in a 1.25" adaptor to feed my ROSs. It pulls the dust from the ROS but there's always residual in the hose. I'm changing that process to a dedicated shop vac so the air velocity will take care of the dust completely.

But recommending stepping down all the way from 6" to 2.5" is BAD advice. The advice should be use a shop vac and move on!

To see the effect of stepping down ducting (including leaving a 6x4X4 wye on the blower) read this. That is only from 6" to 4" so you can just imagine what happens when you go to 2.5" or smaller! You can skip the first part and go to "Some Effects of Decreased Duct Area"

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Originally Posted by Alan Schaffter

But recommending stepping down all the way from 6" to 2.5" is BAD advice. The advice should be use a shop vac and move on! ...

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And sometimes the best advice is to draw from practical experience, throw the engineer out the door and move on. :eek: ;) :D

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Originally Posted by Bill Arnold

And sometimes the best advice is to draw from practical experience, throw the engineer out the door and move on. :eek: ;) :D

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Yup!

http://www.ncwoodworker.net/pp/data/...m/PB050004.JPG

http://www.ncwoodworker.net/pp/data/.../PB0500161.JPG

ain't no chrome on my trailer hitch!

I love this thread. GREAT examples of dust shrouds and lots of good real-world pickup ideas. I have to say, I'll probably pull down a list of all Alan Schaffter's posts sometime soon and start reading--his advice is spot on, and his hands-on designs look great. Some great posts by all involved, this thread will be quite useful for folks!

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Originally Posted by Dennis Leahy

I think what Bill is trying to tell me is that I won't see any dust. I think what Alan is trying to say is to underscore Bill Penz's words, and make me realize that I could have done better with larger ducting, and that there will still be invisible dust particles in the air. And, at this point in the life of my wallet, that means either scrounging for a fan, buying a pleated/pocket filter and some pre-filters and build an air cleaner, or start saving up for a commercial air cleaner unit. I wonder if this cheap one at Grizzly is a waste of money: http://www.grizzly.com/products/g5955

Dennis

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My shop has no windows and no cross ventilation. The whole shop will fill with a haze of fine dust in a matter of minutes. Using a single stage DC with a bag filter only make things worse, and fills the room with dust in a matter of seconds. Therefore I bought the Jet air filter which is similar to the Griz above. There is no way you can remove fine dust fast enough once it is finely dispersed in the air. It does help with the fine dust that settles everywhere after making working in the shop, but the shop still gets very hazy. I've concluded, that if I want my shop to be safe and enjoyable, I need to catch as much dust as I can from the source. Thus, I'm shopping for a cyclone.

For my 2-1/4" stuff I generally use a shop vac (watch for the Ridgids that go for $20 around Christmas time) but, part # 468 should get you where you are trying to go if you are set on using the DC.