# 6" to 4" reducer for dust collection



## furboo (Oct 12, 2015)

I'm working on a DC system with 6" PVC mains. Several of my tools have 4" ports, so I'm searching for a 6" to 4" reducer. I want a smooth transition. This one looks too abrupt:

https://www.woodcraft.com/products/6-to-4-reducer-dust-collection-fitting

My favorite so far is:

https://www.amazon.com/gp/product/B000DZKZA2/ref=s9_dcacsd_dcoop_bw_c_x_3_w

Any other suggestions?


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## coxhaus (Jul 18, 2011)

I bought the one from Woodcraft. It fits inside the 6 inch pipe and my 4 inch hose fits over the 4 inch side. The one on your Amazon link looks like it fits over the pipes so you may need a nipple on the 4 inch side. Let me know how it works out.

I would rather run a 5 inch hose but I have not found a 5 to 6 inch reducer.


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## furboo (Oct 12, 2015)

coxhaus said:


> I bought the one from Woodcraft. It fits inside the 6 inch pipe and my 4 inch hose fits over the 4 inch side.


Thanks Lee. Is the transition from 6" to 4" a step, or does it smoothly transition? It's hard to tell from the photo.


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## furboo (Oct 12, 2015)

I just remembered Ray's trick:

http://www.routerforums.com/tools-woodworking/106218-make-your-dust-collection-fittings.html

I may give this a try.


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## coxhaus (Jul 18, 2011)

It's a step but it is short term for me once I can switch over to 5 inch hose. 

You are moving material from small to large so I am not sure the transition will help. If it was the other direction then it might help.


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## furboo (Oct 12, 2015)

Yeah, you're right, Lee. The transition would have to be too gradual.


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## coxhaus (Jul 18, 2011)

The other thing I should add is not all fittings fit. I took my pipe to Woodcraft to make sure it fit my pipe size.


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## Cherryville Chuck (Sep 28, 2010)

Rob, ideally it should be a cone shape about a foot long or more. It would be something you would have to make or have custom made. The first one shown will cause a great deal of turbulence at the transition point. The system I have has a 6" intake but a double 4" Y just in front of the impeller. 2- 4" lines is still smaller in cross section that 1- 6" line but I think it is a better compromise. The Y works well for me as the DC is in a corner and tools go both ways from there.


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## Herb Stoops (Aug 28, 2012)

furboo said:


> I'm working on a DC system with 6" PVC mains. Several of my tools have 4" ports, so I'm searching for a 6" to 4" reducer. I want a smooth transition. This one looks too abrupt:
> 
> https://www.woodcraft.com/products/6-to-4-reducer-dust-collection-fitting
> 
> ...




Rob the second ones you show is what I used, I got them from Lowes.

If you could make one from pipe it would be better. I used some 7" aluminum stove pipe on some and pop riveted it together and taped the seam with the metalic aluminum duct tape.
Herb


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## hawkeye10 (Jul 28, 2015)

Don't they make rubber ones with band clamps around each end? I can't think what they are called.


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## tomp913 (Mar 7, 2014)

@furboo

My Unisaw has a 6" sheet metal outlet and I used this to go down to 4" for my DC 6 in. to 4 in. Round Reducer or Increaser-R6X4 - The Home Depot 

Because I move the hose between machines, I have the Rockler adapter Dust Right® 4" Tool Port with Clamps, 2 per Pack | Rockler Woodworking and Hardware attached to the reducer, with the quick disconnect mounted on the hose. I have the 90° adapters mounted on my router table and miter saw so it's a matter of seconds to move the hose from one machine to the other.


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## Multiwood (Feb 24, 2013)

Rob I lust recently got the Super Dust Depot and ordered the 6x4 reducer and the 5 x 4 reducer from Rockler (they sell the Super Dust Depot) and the reducers did not fit so I sent them back. I than called Woodcraft they also sell the Super Dust Depot and both reducers I asked then to see if they fit the S D D and they could not get them to fit. I asked why do you sell the reducers that don't fit the SDD. They didn't have an answer. I ended getting fittings at the local Ace Hardware.


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## chessnut2 (Sep 15, 2011)

furboo said:


> I just remembered Ray's trick:
> 
> http://www.routerforums.com/tools-woodworking/106218-make-your-dust-collection-fittings.html
> 
> I may give this a try.


Rob......I had forgotten about this, too. I'm setting up my system, and have been having fits trying to get adapters to fit. Apparently 4 is a variable number. It will take a bit of work to make the forms, but I think worth a try. At this point, I'm not as worried about cost differential as I am about getting stuff to fit! Thanks for the reminder.


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## furboo (Oct 12, 2015)

Cherryville Chuck said:


> Rob, ideally it should be a cone shape about a foot long or more. It would be something you would have to make or have custom made.


Yeah, searching around on acceptable diffuser angles, it looks like a about a 7 degree expansion (from the centerline to each side) should work ok. For a 2" change in diameter, I get about 8-1/4" long (minimum) for the transition. The longer the better. Herb's idea of riveting up a bigger stove pipe sounds good.


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## furboo (Oct 12, 2015)

Herb Stoops said:


> Rob the second ones you show is what I used, I got them from Lowes.


Herb, I see smaller reducers on their website, but not this big (6" x 4"). My closest Lowes is a 40 mile drive, and I like to ensure something is in stock before making the trip. Fortunately, their site is pretty good at what's in stock. 

The closest Lowes that stocks 6" PVC is about 100 miles away (Albuquerque), and I finally got by there yesterday. Of course, now I'm learning I probably need more :frown:


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## furboo (Oct 12, 2015)

chessnut2 said:


> Rob......I had forgotten about this, too. I'm setting up my system, and have been having fits trying to get adapters to fit. Apparently 4 is a variable number. It will take a bit of work to make the forms, but I think worth a try. At this point, I'm not as worried about cost differential as I am about getting stuff to fit! Thanks for the reminder.


The fittings Ray made are one thing, but thinking about this more, I don't know if I'll be able to squeeze down a 6" to 4" by heating it up. That's a pretty big change. I'm going to play around with some smaller (cheaper) PVC first.


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## senebraskaee (Apr 29, 2012)

*Can of worms*

The world of PVC plumbing pipe, dust collector pipe, HVAC pipe, and dust collector hose is a real can of worms. Between incompatible ID and OD it seems like I am forever looking for the elusive silver bullet adapter! I have had good luck with what the plumbing world calls hubless connectors. These are basically a rubber hose with a stainless steel hose clamp on both ends. There is a shielded type that also has a stainless steel cover but that limits the stretch and is to be avoided. These come in all sorts of transition sizes and shapes, including some angles, and are very stretchy for either going over large pipes or will squeeze down for smaller pipes. 
Good luck, I feel your pain.


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## coxhaus (Jul 18, 2011)

Rob what did you end up using for your 6 to 4 inch reducer? 

I am using my reducer at the end of my 6 inch trunk line where it ends on the machine side away from the SDD. I have all my tools setup with quick disconnects with my 4 inch hose. I sold my old DC but kept my hose and quick disconnects as they were already setup. I needed something on the back end of the hose which would fit so I could continue using my quick disconnects. 

Woodcraft sells the quick disconnects which I bought using my old DC.

I did find a 5 to 6 inch reducer which would fit the SDD at Woodcraft. I am running 6 inch pipe to the machines. I know it is not great but I could not find 5 inch pipe. I think I need a little resistance going into the SDD since is meant for 5 inch pipe and I am using 6 inch.


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## furboo (Oct 12, 2015)

@coxhaus I haven't come up with a 6x4 reducer, yet.

I'm still debating whether I want to go the SDD route. The SDD XL comes with a 6" hookup, so at least with that you avoid the 6x5 reducer. See

https://www.oneida-air.com/inventoryD.asp?item_no=AXD002030AXL&CatId={17F46883-40BB-471E-982F-E5F28583241B}

My problem with the SDD is cost and the increase in height of the overall DC, which I'd like to avoid.


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## furboo (Oct 12, 2015)

tomp913 said:


> @furboo
> 
> My Unisaw has a 6" sheet metal outlet and I used this to go down to 4" for my DC 6 in. to 4 in. Round Reducer or Increaser-R6X4 - The Home Depot


Thanks Tom! I may use that until I can come up with something more elegant. My local store actually has those in stock. :smile:


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## Ray Newman (Mar 9, 2009)

gents: I did not make those fittings. The link was sent to me by another woodworker.


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## coxhaus (Jul 18, 2011)

furboo said:


> @coxhaus I haven't come up with a 6x4 reducer, yet.
> 
> I'm still debating whether I want to go the SDD route. The SDD XL comes with a 6" hookup, so at least with that you avoid the 6x5 reducer. See
> 
> ...


I am not sure you will have enough static pressure with the SSD XL. They recommend a minimum of 3 HP. I am worried using 6 inch pipe on the small SDD with getting clogs because it is built for 5 inch pipe. Velocity will slow down in the larger pipe hopefully not enough to clog the bigger pipe. My 2HP Baldor motor pulls 24 amps on 110 so I am on the upper end of the smaller SDD.


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## furboo (Oct 12, 2015)

Ray Newman said:


> gents: I did not make those fittings. The link was sent to me by another woodworker.


Sorry about that, Ray.


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## furboo (Oct 12, 2015)

coxhaus said:


> I am not sure you will have enough static pressure with the SSD XL. They recommend a minimum of 3 HP. I am worried using 6 inch pipe on the small SDD with getting clogs because it is built for 5 inch pipe. Velocity will slow down in the larger pipe hopefully not enough to clog the bigger pipe. My 2HP Baldor motor pulls 24 amps on 110 so I am on the upper end of the smaller SDD.


Thanks Lee, I didn't catch the 3HP recommendation...does it say that on the website somewhere? All I found is:

_The XL cyclone can be used to retrofit nearly make or model dust collector with a 6" diameter intake. This inlet size is typical of 3HP to 5HP single stage dust collectors by manufacturers such as Delta, Harbor Freight, Grizzly, Jet, Powermatic, Shop Fox, etc., but horsepower isn't as important as the actual air volume moving through your ducting.

We recommend an operating airflow of at least 850 CFM for the XL cyclone to effectively separate 99% of debris from the airstream._

I believe I get a bit better than 850 CFM with my current 4" piping and a 2HP motor, and I'm hoping that'll improve with 6" pipes.


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## coxhaus (Jul 18, 2011)

My understanding is about 550 CFM is the max for 4 inch pipe. You can over pipe and lose velocity to where the big chips will not move through the larger pipe and cause clogs. 

You are correct it is airflow not horse power. But it is not just CFM but also FPM. It is a combination of CFM and FPM which creates a good DC. 

My other understanding is you are better on the high side, maximum through put, of a cyclone than on the low side. You get better fine dust removal on the high side of a cyclone because the fine dust is thrown harder against the side of the cyclone to fall down rather than pass through. 

This is all my understanding which could be completely wrong because I am no expert. It is just what I have read the last month.


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## Herb Stoops (Aug 28, 2012)

furboo said:


> Yeah, searching around on acceptable diffuser angles, it looks like a about a 7 degree expansion (from the centerline to each side) should work ok. For a 2" change in diameter, I get about 8-1/4" long (minimum) for the transition. The longer the better. Herb's idea of riveting up a bigger stove pipe sounds good.


Rob ,the sheet metal section is a good place to search for reducers. As another idea is to drop in at a local sheetmetal shop and have one made for you, most shops will do that for a reasonable price.
I found that nothing fits in this business, hoses ,pipes, machine ports,fittings , are all close,but not close enough to work. I have seen where guys use tin cans to make connections. I finally went to stove pipe, you can even make a long taper with it.
Herb


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## furboo (Oct 12, 2015)

coxhaus said:


> My understanding is about 550 CFM is the max for 4 inch pipe. You can over pipe and lose velocity to where the big chips will not move through the larger pipe and cause clogs.
> 
> You are correct it is airflow not horse power. But it is not just CFM but also FPM. It is a combination of CFM and FPM which creates a good DC.
> 
> My other understanding is you are better on the high side, maximum through put, of a cyclone than on the low side. You get better fine dust removal on the high side of a cyclone because the fine dust is thrown harder against the side of the cyclone to fall down rather than pass through.


This makes sense, Lee. 4" PVC would make things a lot simpler and cheaper.


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## CAD-Man (Apr 28, 2013)

Rob try https://www.oneida-air.com/ they have several reducers.

CAD-Man


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## UglySign (Nov 17, 2015)

@furboo

Not sure if you'd make ur own. But I've done a couple cone like shapes
down the road some using this place:

(Truncated) Cone template | www.templatemaker.nl

Enter in the dimensions and you'll get a pdf to print out.
Pretty handy especially when I had to make barrel rings not too long ago.

This one for branches is cool too but it has a price tag

Pipe Joint Template Online Software
http://www.harderwoods.com/pipetemplate.php


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## coxhaus (Jul 18, 2011)

I just got back from a DC class at Woodcraft today. I learned an interesting fact. If you reduce down from 6 inch to 4 inch you need to have 2 open 4 inch ports open at a time. There will not be enough air flowing for the 6 inch pipe from one 4 inch pipe to flow the 6 inch pipe. This is for my size motor and fan. I have a 2 HP motor and 12.25 inch fan. So I need to add a Y pipe and another 4 inch reducer.


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## Herb Stoops (Aug 28, 2012)

UglySign said:


> @furboo
> 
> Not sure if you'd make ur own. But I've done a couple cone like shapes
> down the road some using this place:
> ...


Thanks for posting those, that second one is similar to the free one I had years ago I never used it, but was thinking about making my own fittings at the time.

Herb


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## Herb Stoops (Aug 28, 2012)

coxhaus said:


> I just got back from a DC class at Woodcraft today. I learned an interesting fact. If you reduce down from 6 inch to 4 inch you need to have 2 open 4 inch ports open at a time. There will not be enough air flowing for the 6 inch pipe from one 4 inch pipe to flow the 6 inch pipe. This is for my size motor and fan. I have a 2 HP motor and 12.25 inch fan. So I need to add a Y pipe and another 4 inch reducer.


I have found this to be very true even on my 3hp DC.
Herb


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## whimsofchaz (Jun 6, 2013)

Rob and Lee you can buy the step downs at Lowes or Home Depot. 6-4 and 6-5


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## furboo (Oct 12, 2015)

coxhaus said:


> I just got back from a DC class at Woodcraft today. I learned an interesting fact. If you reduce down from 6 inch to 4 inch you need to have 2 open 4 inch ports open at a time. There will not be enough air flowing for the 6 inch pipe from one 4 inch pipe to flow the 6 inch pipe. This is for my size motor and fan.


Based on Herb's experience on this, I'm guessing it's fairly independent of the motor size and probably more to do with that two 4" pipes have about the same area as one 6".

Thanks for sharing that, Lee. I would not have thought of this immediately.

Did they say anything about 4" vs. 6" pipe for your motor and fan?


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## DesertRatTom (Jul 3, 2012)

I have a giant box of fittings that have odd ID and OD measurements. Take the fittings with you to a woodworking store, there is NO standard for fittings from brand to brand. I have tried to stay with one brand, but even then, many do not fit together properly. I did find that schedule 20, 4 inch pipe seems to work better than thicker walled pipe, at least as far as fittings are concerned. You will likely to have to order this drain pipe from an irrigation store.

And, you will need some good tape to seal the joints. Finally, will you be adding a strand of grounded braided copper wire to the inside of the pipe? If yes, you will need to work out a way of pulling the wire through and connecting between certain joints. A bolt through the ends of a run to secure the interior runs, then connect the bolts with wire on the outside, then tape to seal would be my approach.


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## Herb Stoops (Aug 28, 2012)

DesertRatTom said:


> I have a giant box of fittings that have odd ID and OD measurements. Take the fittings with you to a woodworking store, there is NO standard for fittings from brand to brand. I have tried to stay with one brand, but even then, many do not fit together properly. I did find that schedule 20, 4 inch pipe seems to work better than thicker walled pipe, at least as far as fittings are concerned. You will likely to have to order this drain pipe from an irrigation store.
> 
> And, you will need some good tape to seal the joints. Finally, will you be adding a strand of grounded braided copper wire to the inside of the pipe? If yes, you will need to work out a way of pulling the wire through and connecting between certain joints. A bolt through the ends of a run to secure the interior runs, then connect the bolts with wire on the outside, then tape to seal would be my approach.


The static electricity problem is a myth as many experts have written, for home systems. It is only an uncomfortable situation of getting zapped for the operator, not an explosion hazard.
My DeWalt planer gave a very awakening zap when I first started running it. So I took a #12 wire and ran it from the machinr to the flex duct,(about 3' long) and since the machine is grounded, problem solved. The only other machine I had a problem with was the Performax drum sander, and I did the same for it. 

Tom, I have a giant box of left over fittings too.

Herb


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## Cherryville Chuck (Sep 28, 2010)

I would agree with that Lee. The 6" opening has a cross sectional area of about 28 square inches. One 4" has a cross sectional area of about 13 square inches so 2 four inchers still don't quite equal one 6" and necking a 6" down to one 4" should cause quite a restriction.


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## Herb Stoops (Aug 28, 2012)

Cherryville Chuck said:


> I would agree with that Lee. The 6" opening has a cross sectional area of about 28 square inches. One 4" has a cross sectional area of about 13 square inches so 2 four inchers still don't quite equal one 6" and necking a 6" down to one 4" should cause quite a restriction.


You are right Chuck and if it goes one step further, stepping it down to a 2" or 2 1/2" is even worse. I have seen a lot of people doing that. I have my DC hooked up to the Ridgid spindle sander which is a 2 1/2" port with a 4" reduced to 2 1/2" at the machine. I open 2 more 4" gates 2' down stream from the sander to give it make up air.

Herb


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## tomp913 (Mar 7, 2014)

I wonder, does this work in reverse? The cabinet of my Unisaw slopes to a rectangular opening where there is a sheet metal "boot" which adapts from rectangular to 6" round. I have the adapter I mentioned before to step down to 4" for the DC. I notice that the sawdust in the cabinet seems to build up over time, to the point that I stick the vac hose in from the table top and vacuum out the accumulated sawdust. In comparison, the box under my router table, using the same DC and 4" hose, is always pretty much clean.


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## BrianS (Nov 7, 2004)

tomp913 said:


> I wonder, does this work in reverse? The cabinet of my Unisaw slopes to a rectangular opening where there is a sheet metal "boot" which adapts from rectangular to 6" round. I have the adapter I mentioned before to step down to 4" for the DC. I notice that the sawdust in the cabinet seems to build up over time, to the point that I stick the vac hose in from the table top and vacuum out the accumulated sawdust. In comparison, the box under my router table, using the same DC and 4" hose, is always pretty much clean.


Tom, my Rigid saw does the same thing... I've always assumed it was just dead areas with no air movement that were created around the edges and in the corners. I've read of people putting angled baffles in the saw cabinets sloping towards the pickup to eliminate these dead areas.


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## tomp913 (Mar 7, 2014)

BrianS said:


> Tom, my Rigid saw does the same thing... I've always assumed it was just dead areas with no air movement that were created around the edges and in the corners. I've read of people putting angled baffles in the saw cabinets sloping towards the pickup to eliminate these dead areas.


Brian, 

The saw has an angles floor which slopes towards the outlet and feeds to the rectangular opening in the bottom of the cabinet. BTW the floor panel needs to be removed if you fumble the nut on a blade change as it runs to the bottom - and always to the corner where there's a notch to clear the rounded vertical corner of the sheet metal. After the third time, I got smart(er) and taped the corners closed with some of that shiny tape they use for heating ducts - of course, I haven't dropped the nut since then.


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## Cherryville Chuck (Sep 28, 2010)

tomp913 said:


> Brian,
> 
> BTW the floor panel needs to be removed if you fumble the nut on a blade change as it runs to the bottom - and always to the corner where there's a notch to clear the rounded vertical corner of the sheet metal. After the third time, I got smart(er) and taped the corners closed with some of that shiny tape they use for heating ducts - of course, I haven't dropped the nut since then.


I got tired of fishing that nut out too so I got in the habit of sticking the end of a finger on the end of the arbor and I spin the nut off onto my finger. I haven't dropped one in ages doing it that way.


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## BrianS (Nov 7, 2004)

YES, Been there and done that with the nut!!

Tom, mine too has a sloped bottom to direct the dust over to the opening where the dc hose connects. The bottom, actually a tray, attaches to the bottom of the cabinet, which has straight sides. I was referring to the areas at the bottom of the actual cabinet, just above the dc tray. There is a small lip all the way around that the dust collects on.


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