# Dust Collector Duct Size



## SuperCubber (Feb 23, 2012)

Ladies and Gents,

I know this topic has been discussed numerous times. I've read so many of the discussions, so I don't want to get too deep with this one.

I have (I think) a simple question. I'm planning to purchase the Grizzly G0548ZP (2HP DC with cartridge filter) and G0863 (Cyclone). My question is what size ducting to use 4", 5" or 6".

Here are some details that may help:
Shop size is about 300 sqft
Longest run will likely be about 15-20 feet (including drop) to the tablesaw. The planer and jointer will be a few feet from the cyclone.
Sawstop 3HP PCS
6" Jointer
Dewalt 734 planer

Thanks for any input!


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## craftsman on the lake (Dec 27, 2008)

No expert here but considering my dust collector setup and the shortcomings that it has I'd say that for a 2hp system any of those sizes would be good enough. Although I'd think the bigger the better.

My stop is just a little larger than yours and I've got the same tools. My jointer and planer are close to the dust collector. It gets about all of the sawdust from those. My sawstop is further away with about that 15-20 ft of pipe you mention, 4". Not much gets caught by the collector. I've been thinking of another dust collector just for the saw. Or maybe I should upgrade to one larger unit. I'm been conteplating this issue for a long time and may never act on it.


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## WoodES (Oct 8, 2013)

I would stick with the inlet size of the DC for as long a run as possible and reduce the diameter at the tool. Use 2-45's for elbows and not 90's to make the bends.

I have the 2hp grizzly, 6" inlet, with longest run about 35 ft. with a separator just ahead of the DC . The 6" diameter drops to 4" once the run drops to about 4 ft above the floor. Works fine for most of the work, but I did add a 2nd in-line separator that I use for the Table saw, jointer, & planer. I do plan to upgrade the DC bag to a cartridge sometime this year.


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## clagwell (Dec 20, 2018)

I always find it annoying when someone replies to a question and, instead of answering the question, says that the underlying assumptions are all wrong and that the OP should change his whole approach. Unfortunately, today I'm going to be that guy.

Since you're buying all new, I recommend that you look at the G0703. It's not much more money and should outperform the combination you've picked. The inlet adapter is removable so you have the choice of either 5" or 6" (preferred) duct.

You can't really compare specs. There's a tradition of bogus specsmanship applied to baggers. That 1700CFM is for the fan only. With the collector ring and filter connected it be about half that. The cyclone will reduce it even more. The performance curve shown in the G0703 manual should be realistic.


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## tvrgeek (Nov 19, 2013)

Well, if you don't want to go too deep and are too lazy to use the on-line calculators, you get what you get. 
The answer to your question is "yes, 4, 5 and 6"


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## Redoak49 (Dec 15, 2012)

With that dust collector, 6" pipe is close to the max in terms of maintaining the needed velocity to prevent drop out in the pipe.

I use some 4" dust ports on machines but with a much larger DC and can maintain needed velocity .


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## SuperCubber (Feb 23, 2012)

> I always find it annoying when someone replies to a question and, instead of answering the question, says that the underlying assumptions are all wrong and that the OP should change his whole approach. Unfortunately, today I m going to be that guy.
> 
> Since you re buying all new, I recommend that you look at the G0703. It s not much more money and should outperform the combination you ve picked. The inlet adapter is removable so you have the choice of either 5" or 6" (preferred) duct.
> 
> ...


It's all good. I meant to mention that for height and space requirements, I'm going with this combo. If I could work the G0703 into my space, I would be getting it.


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## SuperCubber (Feb 23, 2012)

> Well, if you don t want to go too deep and are too lazy to use the on-line calculators, you get what you get.
> The answer to your question is "yes, 4, 5 and 6"
> 
> - tvrgeek


You know what would be cool? If you pointed me in the direction of where to find the online calculations…


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## SuperCubber (Feb 23, 2012)

> With that dust collector, 6" pipe is close to the max in terms of maintaining the needed velocity to prevent drop out in the pipe.
> 
> I use some 4" dust ports on machines but with a much larger DC and can maintain needed velocity .
> 
> - Redoak49


Thanks, this is what I'm getting at. I want to go as big as possible without over doing it.


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## ibewjon (Oct 2, 2010)

I have a 2 hp, with pleated filter but no cyclone. I don't have space for the cyclone. About the same size shop as well. I use 5", 26 guage snap lok duct. Long radius 90's. I have read several articles about duct size which stated that 5" is the sweet spot for this size of DC. My system works great. I don't have air measurements at this time, although I plan to purchase instrumentation to do these measurements in the future. The articles stated that there is not enough volume with 4", and air speed drops too much with 6". A 5 hp machine will be completely different. Good luck.


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## tvrgeek (Nov 19, 2013)

GOOGLE "dust collector calculations"



> Well, if you don t want to go too deep and are too lazy to use the on-line calculators, you get what you get.
> The answer to your question is "yes, 4, 5 and 6"
> 
> - tvrgeek
> ...


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## JackDuren (Oct 10, 2015)

I took the dual 4" off and put a 6" that reduced to a 5" and ran 5" down the as a main and branched off with 4" to the tools. Works great and can run 2 machines at one time.or run the router table with ports on top and bottom at one time….


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## BattleRidge (Oct 22, 2017)

With your shop and equipment, the DC / cyclone combo should be capable of servicing your needs without much difficulty. While there can be a lot of technical considerations and you can fine-tune everything for the maximum possible performance, my personal experience is that you can get great dust collection without a need to get overly complicated - the basics will sometimes do (but not always).

I have the Grizzly G0548Z dust collector and a Super Dust Deputy cyclone (each purchased at a great price) and while my original thought was to install 6" dust collection piping, the high cost of the fittings caused me to reevaluate. In the end I ran a short section of 6" pvc and 6" flexible DC hose between the DC and cyclone and a 5" flexible DC hose (same size of the SDD intake fitting) to an adapter to two 4" PVC pipes (which I already had on hand from a previous project). Each of the 4" PVC lines are connected to my equipment via wyes (quite affordable) with a blast gate and 4" flexible hose. I typically run between 1 - 3 blast gates open simultaneously with great collection from each of the machines I have in use. While I might be able to 'improve' the collection specs, my dust removal is MORE than adequate and while I originally set things up on a trial basis, it has performed exceptionally well and I have no plans to change anything, except to possibly place an additional wye & blast gate for a drill press that was recently added to my shop. In essence, you can probably go with a variety of different set-up's and be quite satisfied so don't get overly worried - though at the same time, it can be good to do things right the first time.


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## SuperCubber (Feb 23, 2012)

> I have a 2 hp, with pleated filter but no cyclone. I don t have space for the cyclone. About the same size shop as well. I use 5", 26 guage snap lok duct. Long radius 90 s. I have read several articles about duct size which stated that 5" is the sweet spot for this size of DC. My system works great. I don t have air measurements at this time, although I plan to purchase instrumentation to do these measurements in the future. The articles stated that there is not enough volume with 4", and air speed drops too much with 6". A 5 hp machine will be completely different. Good luck.
> 
> - ibewjon


Very helpful, thanks!


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## idahotinker (Aug 2, 2013)

http://billpentz.com/woodworking/cyclone/

This is a like a course and I spent a lot of time studying it before I built my system. Bill makes a compelling case for larger air volumes that require larger ducting. However, after using my system for about a year now, I have learned that there is a distinction between dust collection for safety and air quality and the convenience of gathering up sawdust as best I can. The fine particulates are the health risk, and they are so fine and light that velocity is not a huge issue (assuming I understand Bill's arguments). However, to move planer chips and the like, velocity is important, but that velocity comes at a cost of sheer volume. My 1900 com 2HP cyclone system means little if I crimp the ducts down too far. I chose to run 7" as far as I could, but that's because of the "potential" of my cyclone. I run as close to my machines as I can, then transition to 4 and 5". I try not to use too much flex. I got my fittings and pipe from a local sheetmetal supplier. They were great to work with. I guess my point is that if your primary goal is to save your lungs, the approach may be different. Ideally, the system design would not only pick up as much of the larger "sawdust" as possible, but capture, move, and filter the air before it is returned to the shop. Sorry for the long answer…which really doesn't help you much


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## DaveM123 (May 2, 2020)

I have the Grizzly 0548ZP in a smallish shop. Basically it's 18×24. I ran 4 inch pvc with separate blast gates for my ts, rt, bs, planer, drill press and floor sweep. I also have a chip separator. I typically only run with one blast gate open. This setup works fine for my needs.


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## Canucksar (Jan 15, 2013)

Don't be surprised if you don't have a good collection at the SawStop I have a 5HP 8" duct reduced at the saw and it still sucks (not) I will be reworking its collection ASAP as the OME is crap.


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## Redoak49 (Dec 15, 2012)

I have a 5 hp DC hooked to my SawStop PCS and works fine. Does it get every speck of dust … No. But it gets a large per cent. There is a big difference in expectations for dust collection at tools. For me, if I get 95%, I am happy.


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## therealSteveN (Oct 29, 2016)

> Well, if you don t want to go too deep and are too lazy to use the on-line calculators, you get what you get.
> The answer to your question is "yes, 4, 5 and 6"
> - tvrgeek


WOW, such a judgemental informative answer. No included link to one of these wonder calculators. Had you considered the OP didn't know about them?



> I would stick with the inlet size of the DC for as long a run as possible and reduce the diameter at the tool. Use 2-45 s for elbows and not 90 s to make the bends.
> 
> I have the 2hp grizzly, 6" inlet, with longest run about 35 ft. with a separator just ahead of the DC . The 6" diameter drops to 4" once the run drops to about 4 ft above the floor. Works fine for most of the work, but I did add a 2nd in-line separator that I use for the Table saw, jointer, & planer. I do plan to upgrade the DC bag to a cartridge sometime this year.
> 
> - WoodES


A much better answer, actual information given.


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## Redoak49 (Dec 15, 2012)

I think the answer of 4, 5 or 6 inch duct is what I have seen people on LJ use for similar dust collectors. What you use depends on your expectations and how much you spend. Using 6" PVC or metal pipe would be the best but not much better if at all over 5" . The 4" will also work.

Someone posted the Bill Pentz link which is a great start and if he has read other posts should have the information he needs.

If you want A quick answer, people will here will give you opinions. There are only one or two I would really trust. Many provide anecdotal opinions about their systems with no good measurements to back it up. There are some with good technical information like A poster call clagwell.

A comment for BattleRidge-you could greatly improve your system by doing a better job on the flex hose. You have a number of fairly tight bends with ribbed flex hose and these definitely hurt performance.


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## SuperCubber (Feb 23, 2012)

Thanks for all the responses.

I've read some Bill Pentz and it's good information. I was under the impression that there was an easy answer to my question. Obviously, I can now see that that isn't the case.

I don't have a lot of time to spend at a computer screen reading, so most of my online reading is on a mobile device, which does not work well on the Pentz site. I'll have to make more time for it on my PC.

Anyway, I'm not too worried about the cost (within reason). I'm mostly trying to figure out if 6" is too big to have the flow I need and if 5" is the sweet spot. I'm leaning toward 5", but I'm going to continue to research.


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## ibewjon (Oct 2, 2010)

6" is about 50% larger than 5", even though it doesn't sound like it. That is a lot more air to move.


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## BattleRidge (Oct 22, 2017)

> A comment for BattleRidge-you could greatly improve your system by doing a better job on the flex hose. You have a number of fairly tight bends with ribbed flex hose and these definitely hurt performance.
> 
> - Redoak49


While I might be able to improve the technical spec numbers in my system, in real-world functionality the system does everything I need it to do and more. I did a lot of research and planning on dust collection options and know that there are better (and more $$$ & space-consuming) options, but in setting up my shop at my budget as a retiree, the ideal set-up gave way to real-world needs and affordability. While I originally put my system together on an easy-to-change trial basis, it has worked exceptionally well and I used the saved funds for additional woodworking tools and equipment. My shop is set-up pretty much as I want it with everything working very well together, but should I ever need to tweak things for better performance, replacing the flex hose and modifying the layout can be an option.

In the end I got a great deal on my G0548Z ($240 brand new from the original owner that bought it new but never placed it into service - $634 delivered if purchased from Grizzly), the Super Dust Deputy ($25 at a dealer's 'scratch & dent sale', the box was damaged but the SDD was in perfect condition - $170 new) and the PVC pipe and some fittings were left over from another project and already on hand - needing just a few items to tie everything together.

I guess I look at my shop in the way I look at my vehicle - what works. I could spend of money on a fancy Porsche that would go fast and look pretty - but my Toyota Tundra cost a lot less, performs a lot more functions, gets me in and out of my 2,000 ft driveway in the wintertime without hesitation, and still looks great after 10 years.


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## Redoak49 (Dec 15, 2012)

BattleRidge….I am not suggesting that you spend more money or make major changes. I am saying that sharp bends in the flex have a significant impact on performance. The one in your picture is an example.



>


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## AndyJ1s (Jan 26, 2019)

If shop space is an issue preventing a cyclone separator, take a look at the Oneida Mini Gorilla. Same 1.5HP, with cyclone and HEPA filter, in a lot smaller space (with 22 gal collection bin). The longer tapered cyclone is more efficient than shorter tapered cyclones.

I roll mine around and hook it up where I need it. Since my shop has to house the SUV overnight, all of my machines are on mobile bases out of necessity, and fixed ducting is a non-starter. But the MG can be used with fixed ducting too, in a small shop. It's inlet is 5". CFM and suction are more than enough for a Hammer A3-41 16" jointer/planer. I am very happy with it.

Without a cyclone separator, filters will clog rapidly and actual CFM will plummet. The paddles on the pleated filters will help, but won't dislodge the fine stuff that chokes off airflow through the filter. You really need to use compressed air from the outside anyway to clean it and restore CFM/suction.

I trust Oneida's CFM ratings/curves a lot more than I trust Grizzly's (or any other Chinese import's).


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## Redoak49 (Dec 15, 2012)

> I trust Oneida s CFM ratings/curves a lot more than I trust Grizzly s (or any other Chinese import s).
> 
> - AndyJ1s


I agree as I tested my Oneida with a hot wire anemometer to get a performance curve and was about 10% different than the Oneida.


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