# HF dust collector flow measurements



## furboo (Oct 12, 2015)

I wanted to keep track of modifications to my new HF DC, so I built a very simple manometer this morning. My only mod so far is the Wynn filter. Pictures below.

*Initial measurements*

As close to the HF inlet as I can measure (see picture staticp.jpg), I get 6" H20, which if my calculations are correct, translates to 975 CFM. Note that I live at 7,200' altitude, so any DC will suffer a lot in performance. I'm also using a 4" pipe, a big no-no according to DC experts, but it makes hooking up to my tools a lot easier.

I then measured at the end of a Rockler 4' long expandable hose. See pic hose.jpg (it's unhooked in the picture) and

Dust Right® 4'' Dia. Expandable Hoses | Rockler Woodworking and Hardware

This drops the performance to 2.5" H20, or about 630 CFM. Ouch. This was with the hose compressed and no bends. So, I guess I gotta change how I bring the DC to my tools.

Anyway, as I modify my DC, I want to keep track of performance changes.

*Some details*

The manometer itself 1/2" tubing with filled with water, with green food coloring. I step that down to a long section of 3/8" tubing (to reach anywhere in my shop), then to 1/4" tubing. I drilled a 1/4" hole in a 4" hose splice, and that's where I measure static pressure. Again, see staticp.jpg. The markings on the manometer are 1/2" apart. Pretty simple.

My measurements may be a bit off, because I need to seal the attachments. But I doubt that they're off that much.

Converting inches of H20 to CFM requires some assumptions, the biggest being current air density. But that doesn't really matter. The bottom line is you want to maximize inches of H20 (the difference in the water levels), and the manometer lets you measure any changes to the DC system.


----------



## furboo (Oct 12, 2015)

I should mention that I got the idea for the simple manometer from






where he explains using it for keep track if the Wynn filter needs cleaning. I'll hook it up that way do once I'm happy with my other DC mods.


----------



## Cherryville Chuck (Sep 28, 2010)

That's a great idea to make one for monitoring the filter's condition Rob. Thanks.


----------



## sunnybob (Apr 3, 2015)

Rob, home made manometers arent all that accurate. OK so long as you only use the one and only compare it to your other measurements, but often not transferable to another set up.
Any large plumbing or gas fitting supplier will sell a proper manometer as used for taking gas pressure readings.
This is just the first link I found
https://www.amazon.com/General-Tools-HG15-Hydrogauge-Manometer/dp/B001TOHT78


----------



## Eugd (Jan 29, 2015)

You might want to make one of these carts but you will have to add a sdd, best thing I did, I have great suction, no loss, I fiddled with my dust collection until I finally bit the cart. I work in a 2 car garage I was going to add ducting but still fiddling with my layout in the shop.


----------



## furboo (Oct 12, 2015)

sunnybob said:


> Rob, home made manometers arent all that accurate. OK so long as you only use the one and only compare it to your other measurements, but often not transferable to another set up.
> Any large plumbing or gas fitting supplier will sell a proper manometer as used for taking gas pressure readings.
> This is just the first link I found
> https://www.amazon.com/General-Tools-HG15-Hydrogauge-Manometer/dp/B001TOHT78


Bob, I'm not claiming that my measurement of water level or CFM is accurate. I certainly don't want HF to sue me for misrepresenting their DC performance :surprise:

My motivation is to see the effect of changes in DC setup, and I claim homemade is good enough to do this, at least for changes large enough to have a noticeable effect on dust collection. The fact that I'm doing this at 7,200' altitude will mean my water level and CFM numbers will be far from most others on this forum.

The manometer in your link might add precision to the readout, but will not compensate for the assumptions required to back out CFM from the water height. I suspect these assumptions create bigger errors than from reading the water level. If you really want to increase the accuracy of the reading, save your $27.99, use longer tubing on a tilted table, and a well characterized fluid.


----------



## furboo (Oct 12, 2015)

Eugd said:


> You might want to make one of these carts but you will have to add a sdd, best thing I did, I have great suction, no loss, I fiddled with my dust collection until I finally bit the cart. I work in a 2 car garage I was going to add ducting but still fiddling with my layout in the shop.


Nice setup, Eugene. My DC is on rollers, and it looks like I'll keep it that way when I add a chip collector. It looks like you're using smaller bag than stock, and I was considering the same thing, in order to shorten the DC.


----------



## RainMan 2.0 (May 6, 2014)

Rob I was thinking it wasn't so much about accuracy, but to monitor whether or not an improvement has taken place .


----------



## Cherryville Chuck (Sep 28, 2010)

I certainly never thought of it as being able to take an accurate reading but it is an excellent way to monitor system and filter performance since you'll obviously take a reading when the system is new and that will allow you to be able to track performance over time and with filter cleanings. Since the set up is static it will respond accurately to changes even though it isn't particularly accurate in terms of absoluteness. That's all I would really be interested in knowing, since there is very little I can do to change the system, is to be able to monitor how well it is performing under it's relatively fixed parameters.


----------



## furboo (Oct 12, 2015)

RainMan 2.0 said:


> Rob I was thinking it wasn't so much about accuracy, but to monitor whether or not an improvement has taken place .


Yes, exactly.


----------



## furboo (Oct 12, 2015)

Basically, I plan to add a chip collector, rearrange the motor location to do so, and maybe upgrade to the Rikon impeller. I want to be able to monitor the changes, hopefully something better than "gee, that's suckin' real good now..." :smile:

If I'm bored I might put the original bag filter on to see if there's much difference between it and the Wynn.

I like the filter monitor thing too...that's what got me thinking about this.


----------



## Eugd (Jan 29, 2015)

It appears to me that you are concerned with suction? If you want to maintain good suction trust me, I did everything you stated that you want to do in the future and my suction was terrible until I redesign things and reduced the run and opened up the blower and cut away the air restricters. My unit is a shop fox 1.5 hp not a 2hp like the your system and I get almost the full cfm for the unit. 
I had the rockler chip collection system I bought a year ago, and most of the dust and chips still went to the bag, then I added a theine baffler, it helped but if I had a project that I needed cut plywood or mdf, the baffler and the chip collector did nothing except clog my wynn filter, I ended up cleaning out the bag and the filter each month, since mounting the blower on the sdd then mounting it on the 30 gallon drum. Not only has my suction stayed strong, the only time my bag sees any type of use is when I blow out my filter. My setup is on a cart that came with the system I just added some extra wood to it to support the weight of the motor.


----------



## Bob Adams (Jul 5, 2014)

Before I did the impeller swap on my HF unit I bought a cheap anemometer to track the changes. To me it made sense, if for nothing else than to provide me with "proof" that I could show my wife that I needed a bigger and better DC. That plan didn't work out. However it did show that with the new impeller I went from an average of 325 cfm on 3 drops to 675 cfm. I use the anemometer occasionally monitor how the it is doing, because you never know when an opportunity for an upgrade might present itself. :wink: While I would like a bigger and better unit the DC does a pretty good job, and being able to track your changes make perfect sense.


----------



## furboo (Oct 12, 2015)

Eugd said:


> It appears to me that you are concerned with suction? If you want to maintain good suction trust me, I did everything you stated that you want to do in the future and my suction was terrible until I redesign things and reduced the run and opened up the blower and cut away the air restricters. My unit is a shop fox 1.5 hp not a 2hp like the your system and I get almost the full cfm for the unit.
> I had the rockler chip collection system I bought a year ago, and most of the dust and chips still went to the bag, then I added a theine baffler, it helped but if I had a project that I needed cut plywood or mdf, the baffler and the chip collector did nothing except clog my wynn filter, I ended up cleaning out the bag and the filter each month, since mounting the blower on the sdd then mounting it on the 30 gallon drum. Not only has my suction stayed strong, the only time my bag sees any type of use is when I blow out my filter. My setup is on a cart that came with the system I just added some extra wood to it to support the weight of the motor.


Thanks Eugene, I'm hoping the Thein will be enough, but it's good to hear that a SDD was such an improvement. But I'm not sure what you're referring to in "cut away the air restricters." In the blower? I haven't opened that up, yet.


----------



## Eugd (Jan 29, 2015)

I did that on my setup because it stepped it down to 5" on the unit but it was a 6 inch opening, I removed the cross bars and the tapers to get a full 6" meeting the 6" opening in the sdd. The way the sdd is set up there is no way for anything to hit the blades of the impeller, however I don't advise you to do it on your setup, because even with the chip separator things will pass the through the chip separator even with the theine baffler. I know people use successfully, I personally did not, and because most of my projects created fine dust the filter and bag needed constant cleaning or my suction suffered. Now I been running this for several months and have cleaned it out once even though I empty the barrel often. It's your setup, do as what ever you like but I'm not concerned checking my cfm loss anymore.


----------



## Daikusan (Apr 12, 2013)

Is the HF DC 110 or 220? The info on HF site dosent say.


----------



## Lucky Irish (Mar 7, 2015)

The HF unit is 120v.


----------



## MYB506 (Dec 5, 2012)

In my younger days I worked as a Gas Technician for a large natural gas distribution company and the manometers we used to set gas pressures to homes and appliances was very similar to the one Rob made. Our's were made in the company's carpenter shop. As long as you have a proper inch ruler to measure with and set the water level at zero it will be more reliable than a pressure gauge.


----------



## coxhaus (Jul 18, 2011)

furboo said:


> Basically, I plan to add a chip collector, rearrange the motor location to do so, and maybe upgrade to the Rikon impeller. I want to be able to monitor the changes, hopefully something better than "gee, that's suckin' real good now..." :smile:
> 
> If I'm bored I might put the original bag filter on to see if there's much difference between it and the Wynn.
> 
> I like the filter monitor thing too...that's what got me thinking about this.


Can you still buy the Rikon impellers? I saw posted on a different site Rikon won't sell you an impleller unless you can prove you own a Rikon DC.

The Rikon impleller is 12 inches instead of 10. I would think it would be a great upgrade. Probably the best improvement you can make to a HF DC.


----------



## furboo (Oct 12, 2015)

coxhaus said:


> Can you still buy the Rikon impellers? I saw posted on a different site Rikon won't sell you an impleller unless you can prove you own a Rikon DC.


Yea, I saw on a thread somewhere that you had to provide the Rikon DC serial#, but can't find the thread now. Has anyone bought one recently?


----------



## DesertRatTom (Jul 3, 2012)

coxhaus said:


> Can you still buy the Rikon impellers? I saw posted on a different site Rikon won't sell you an impleller unless you can prove you own a Rikon DC.


Several posts just say order the parts numbers and do not mention the HF unit. It also says to make a phone call. Here's the info again.

_Rikon - 877-884-5167 - ask for parts, do NOT talk about your HF-DC, state you need an impeller for a 60-200 DC, part #22 for the impeller. Part #26 for a new bolt and part #27 for the "spring washer". You can use the old bolt and washer - I did - but bought the new ones anyway [why you ask - because I am that...]. Total cost for all of it - $120.27 including S&H. Download the Rikon Manual for a 60-200M3R.PDF and check for yourself _


----------



## Cherryville Chuck (Sep 28, 2010)

MYB506 said:


> In my younger days I worked as a Gas Technician for a large natural gas distribution company and the manometers we used to set gas pressures to homes and appliances was very similar to the one Rob made. Our's were made in the company's carpenter shop. As long as you have a proper inch ruler to measure with and set the water level at zero it will be more reliable than a pressure gauge.


Good point Mark. Unless the composition of water is not stable and the laws of physics suddenly change then there is absolutely nothing that can go wrong with it, unlike a mechanical meter. I'm a power engineer and many of the ones used in my trade also use a fluid and but as Rob pointed out earlier, they are sloped so that changes are easier to read.

Re: needing a serial number to order a part: if anyone near you sells Rikon go take the number off a new one. Not exactly the most ethical thing to do but I'm not sure what they have against selling impellers.


----------



## furboo (Oct 12, 2015)

Cherryville Chuck said:


> Re: needing a serial number to order a part: if anyone near you sells Rikon go take the number off a new one. Not exactly the most ethical thing to do but I'm not sure what they have against selling impellers.


I'm guessing they don't like you paying $150 for the HF (on sale), plus $120 for their impeller, for a total of $270, instead of $400 for whole the Rikon DC. Aside from the impeller, paint scheme, filter bag (which you should replace with a Wynn), it's hard to see a difference between the HF and Rikon.

On the other hand, I would think they make some profit off selling just the impeller.


----------



## coxhaus (Jul 18, 2011)

I would think jumping from a 10 inch blade to a 12 inch on a DC should make a huge difference.


----------



## Bob Adams (Jul 5, 2014)

furboo said:


> Yea, I saw on a thread somewhere that you had to provide the Rikon DC serial#, but can't find the thread now. Has anyone bought one recently?


I bought mine a little over a year ago. I too had heard that I would need the serial # off of a Rikon DC to complete the order. It sounded like a bunch of nonsense, so I called and I asked when ordered. The person that I spoke to, chuckled and said "We've heard that too", then they charged me $120.00 and sent me the impeller.


----------



## RainMan 2.0 (May 6, 2014)

Guys when I seen the difference in size with those two impellers , I didn't think the larger one would fit in the same chassis? 
Seems kind of strange that they left all that excessive room in there . I guess if you want a model with more output , they just name it differently and have that bigger impeller installed ?
Wonder if my General DC can have a larger impeller installed?


----------



## furboo (Oct 12, 2015)

RainMan 2.0 said:


> Guys when I seen the difference in size with those two impellers , I didn't think the larger one would fit in the same chassis?
> Seems kind of strange that they left all that excessive room in there . I guess if you want a model with more output , they just name it differently and have that bigger impeller installed ?


In one of the many threads I've read on this, someone pointed out that a smaller impeller would allow bigger chips to pass through. I doubt that's what HF's "R&D department" was thinking, but I still probably wouldn't change the impeller if I didn't have a chip collector.


----------



## RainMan 2.0 (May 6, 2014)

furboo said:


> In one of the many threads I've read on this, someone pointed out that a smaller impeller would allow bigger chips to pass through. I doubt that's what HF's "R&D department" was thinking, but I still probably wouldn't change the impeller if I didn't have a chip collector.


That makes sense then . They leave extra room for the chips that may go threw . 
I wonder how much cfm you loose with a chip collector?


----------



## JFPNCM (Dec 13, 2009)

@furboo

I would be very interested in the readings for the Wynn vs. the original filter bag, including the specs for the bag. 

Thanks for the post, very informative.

Jon


----------



## Daikusan (Apr 12, 2013)

Lucky Irish said:


> The HF unit is 120v.


Thanks Mike :smile::smile:


----------



## furboo (Oct 12, 2015)

RainMan 2.0 said:


> I wonder how much cfm you loose with a chip collector?


I'll take a measurement with my old 30 gallon fiber drum with the Rockler top, soon. I want something shorter, so I'm also going to use a smaller drum (Tom posted it on another thread), with a Thein added, which hopefully I'll find time to put together in the next few weeks.


----------



## furboo (Oct 12, 2015)

RainMan 2.0 said:


> That makes sense then . They leave extra room for the chips that may go threw .


I was kidding about HF's R&D Department. I'm guessing HF got a good deal on the 10" impellers and didn't put too much thought into it. I don't have a chip collector yet, I hear plenty of chips hitting the 10", and I'm pretty careful not to suck up anything too big.


----------



## furboo (Oct 12, 2015)

JFPNCM said:


> I would be very interested in the readings for the Wynn vs. the original filter bag, including the specs for the bag.


Jon, bring down some Pinot from Oregon and you got a deal :smile:

I will do it some time. The bag I have is the 5 micron that comes with the HF DC. I did splurge on the Wynn and got the new, easier to clean, 222 series (35BA222NANO). See

https://wynnenv.com/woodworking-filters/new-222-filters/


----------



## JFPNCM (Dec 13, 2009)

furboo said:


> Jon, bring down some Pinot from Oregon and you got a deal :smile:
> 
> I will do it some time. The bag I have is the 5 micron that comes with the HF DC. I did splurge on the Wynn and got the new, easier to clean, 222 series (35BA222NANO). See
> 
> https://wynnenv.com/woodworking-filters/new-222-filters/


Rob: How close is "down"? It tends not to travel well in my comapny. :grin:


----------



## furboo (Oct 12, 2015)

*Pressure drop for 30 gallon drum chip separator*

This evening I measured the peformance drop for an empty 30 gallon fiber drum chip collector, that has Rockler connectors on it. The photos below show the hookup with the collector, and I also took a measurement with just the 4" connection hose, roughly in the same position.

*Just the numbers*

Disclaimer: As always, my CFM numbers are computed from the manometer reading, based on lots of approximations. They're meant to just give a feel for the performance changes.

Baseline: 5-15/32" H2O, 931 CFM
Just hose: 3-1/32", 692 CFM (239 CFM decrease)
Hose w/collector: 1-7/16", 477 CFM (another 215 CFM decrease, total 454)

*Comments*

Note that if your system operates at a different baseline CFM (manometer reading), you WILL get a different decrease in CFM (or pressure drop).

It really surprises me that the connection hose is as bad (or worse) than the collector. I'm wondering if using PVC, even for these short runs, would really pay off.

I was much more careful measuring the baseline (nothing connected). In my first post of this thread, I got 6", rather than 5-15/32. But in that first post, I didn't use a ruler and wasn't very careful. Regardless, whether the difference is because I was more careful this evening, or cause I had a beer with dinner, change in atmospheric pressure, humidity, my incompetence, etc., well... ya'll get what you pay for.

The Rockler hookups are here:

Dust Right® 4" Dust Separator Components | Rockler Woodworking and Hardware

I once used this collector with my Rockler DC, that I've since sold. I plan on building a different collector, based on a drum that DesertRatTom found, discussed in another thread.


----------



## coxhaus (Jul 18, 2011)

Rob what you are seeing is confirming what Onedia told me so thanks for confirming it. Use the least amount of flex hose. I wanted to order 25 feet of flex hose so I could connect to what ever and they recommended against it. They recommended to use smooth wall pipe with the least amount of flex hose. I plan to use 6 inch light weight pvc crush 200 pipe. It is $20 for ten feet as I have bought 2 sticks of pipe. I just need to plumb it.


----------



## furboo (Oct 12, 2015)

coxhaus said:


> Rob what you are seeing is confirming what Onedia told me so thanks for confirming it. Use the least amount of flex hose. I wanted to order 25 feet of flex hose so I could connect to what ever and they recommended against it. They recommended to use smooth wall pipe with the least amount of flex hose. I plan to use 6 inch light weight pvc crush 200 pipe. It is $20 for ten feet as I have bought 2 sticks of pipe. I just need to plumb it.


That's interesting, Lee. I'm currently using a long hose to connect to everything, which in the first post I also measured a big drag on the system. I was really hoping to put this DC on the other side of the wall, because I'm tight on space, with a connection port through the wall and still use the flex hose. That's just not going to work well.

In this last measurement, part of the hose drag is the two 90 deg. (roughly) bends. The other component is the bumpiness of the hose inner wall, which must disturb the airflow quite a bit. I just didn't think it would be as bad as the collector.


----------



## Tonto1 (Nov 10, 2016)

It sounds like we need to look into redesigning the fitting into the chip barrel. Instead of going through the top with a 90 degree bend. Maybe we could build an adapter for the side of the barrel. A straight coupler that points 45 degrees down as it enters through the side of the barrel. That would get rid of 1 90 degree turn. It would mean cutting out an oval hole in the side of the barrel to accommodate the straight coupling. Sounds like it would be difficult to calculate. Maybe use a piece of cardboard to practice on then use it as a template. Again, just thinking out loud! Maybe we could ask Rockler to design it and offer it for sale. Or any of the sponsors.


----------



## Tonto1 (Nov 10, 2016)

It would look like the fitting on the dust collector above, except angled down into the barrel to induce the spin/cyclone effect.


----------



## coxhaus (Jul 18, 2011)

Rob if you pull the "Y" connector off the fan unit you may be able to use a 6 inch pipe which would work better connecting to your chip separator.


----------



## Tonto1 (Nov 10, 2016)

The exit on the DC is 5 inches.


----------



## coxhaus (Jul 18, 2011)

I had a hard time finding 5 inch pipe so I am using a 5 to 6 inch reducer for my SDD and using 6 inch pipe. The 5 inch pvc pipe I found was expensive at about just under $5 per foot.


----------



## Herb Stoops (Aug 28, 2012)

The diameter of the port on the machine greatly effects the air flow. Reducing a hose down to say 2 1/2" requires additional air flow to keep the chips from settling out before they reach the dust bin. I open a blast gate just down range from the machine to add to the air flow. If you are hooking directly from machine to dust collector with a long hose and reducing the diameter to a small port on the machine, you will get a very reduced air flow. 
I piped the shop with 3 main 6" PVC runs and put drops in various places for machines, then reduced with short lengths of flex from machine to DC 6" duct. When possible I used 6" flex i.e. table saw,radial arm saw,short 4" directly to some machines and 4" reduced to 2 1/2" to others.
90deg. elbows and T's drasticaly reduce air flow.

I like that link to the Wynn new clean out filter system you posted here. I use the wynn filters too and they are great.
Herb


----------



## furboo (Oct 12, 2015)

coxhaus said:


> Rob if you pull the "Y" connector off the fan unit you may be able to use a 6 inch pipe which would work better connecting to your chip separator.


Oh yeah, the Y is going. Once that's gone, someone (maybe on this forum), expanded the 5" port to 6". I suspect they chopped of the 5" fitting, expanded the hole in the housing on the impeller, and put on a flange that take a 6" pipe.

It's a bummer that HF used just a 5" hose between the impeller output and bag/filter input. But like johnnie_dr and others, I'm next going to build a cart to lift the motor up to make this connection as short as possible. We'll see how much of an improvement that gives. Obviously, this also allows me to put a chip collector underneath.


----------



## furboo (Oct 12, 2015)

Herb Stoops said:


> The diameter of the port on the machine greatly effects the air flow. Reducing a hose down to say 2 1/2" requires additional air flow to keep the chips from settling out before they reach the dust bin. I open a blast gate just down range from the machine to add to the air flow.


That's a great idea, Herb.


> If you are hooking directly from machine to dust collector with a long hose and reducing the diameter to a small port on the machine, you will get a very reduced air flow.


Yep :frown: I was hoping that since I have a fairly small shop, the loss through a short 4" flex hose wouldn't be that bad. But it is.


> I piped the shop with 3 main 6" PVC runs and put drops in various places for machines, then reduced with short lengths of flex from machine to DC 6" duct.
> When possible I used 6" flex i.e. table saw,radial arm saw,short 4" directly to some machines and 4" reduced to 2 1/2" to others.


You've got a powerful, 3HP DC. But I do have a small shop, maybe if I just ran the 6" PVC to one or two locations, and then brought my tools to them. The big dust makers I have are a jointer, planer, TS, router table. All are on wheels.

I've also got the Bosch 4100...how did you hook a 6" flex hose to it? Mine has a 2 1/2" port.

Great info, Herb. Thanks a lot.


----------



## Herb Stoops (Aug 28, 2012)

furboo said:


> That's a great idea, Herb.
> 
> Yep :frown: I was hoping that since I have a fairly small shop, the loss through a short 4" flex hose wouldn't be that bad. But it is.
> 
> ...


Rob, on the Bosch 4100 I made a box of 3/4" plywood and cut it to fit between the power cord cleats on the back of the saw. Then made a couple of "U" shaped blocks that fit the cleats and screwed them to the plywood sides.
The plywood covers the whole opening in the back of the saw. Thus you are drawing air out of the whole cavity under the saw. The 2" is shooting into the 6" opening and air is being pulled in from the front and sides and anywhere there is an opening in the base of the saw, so the air flow isn't diminished by the 2 1/2" opening, and is removing sawdust that doesn't get taken out by the 2 1/2" exhaust.
It seems to work well.
I cut a hole in the plywood and used a 1/2 of a 6" PVC coupling to connect to the flex. 
You are really doing a good job thinking this thing out,Rob.
You will find that nothing is standardized in this field. Nothing fits together, 4",6" is not the same from one manufacturer to another. Air flows are not accurate from manufacturers as there is no standard to set a bench mark. You have the right approach to test and see how your system performs from one condition to another.
Keep up good job.
Herb


----------



## furboo (Oct 12, 2015)

Very nice, Herb. It looks like I could do the same for the Bosch, even with the Gravity Rise stand.


----------



## furboo (Oct 12, 2015)

*Wynn filter is awesome*

@JFPNCM This evening, I measured the pressure with the original HF 5 micron bag. No difference with the Wynn, to within 1/32" H20. I'm REALLY surprised. Again, I've got the new 222 series filter:

https://wynnenv.com/woodworking-filters/new-222-filters/

All I can say is these filters are awesome.

Jon, it's not that far from OR to beautiful New Mexico, and it's a nice 17 deg. here right now. Don't let the Pinot freeze on your way down :grin:


----------



## woodknots (Mar 7, 2012)

@Herb Stoops

Don't mean to hijack this thread but how did you attach the box to the back of the 4100? Do you have a side view?


----------



## Herb Stoops (Aug 28, 2012)

furboo said:


> Ohsomeone (maybe on this forum), expanded the 5" port to 6". I suspect they chopped of the 5" fitting, expanded the hole in the housing on the impeller, and put on a flange that take a 6" pipe.
> 
> .


I know a person who took the metal plate off the fan housing and replaced it with a 3/4" BB plywood with a 6" hole and a piece of 6" pipe for a nipple. He showed me where on the end where the pipe goes inside he routed a 1/4' radius around the hole to keep from having air turbulence from a square edge,which disrupts air flow.
To fasten the nipple he drill small holes and tacked the inside of the pipe to the BB plywood. He also put some sealant/caulking around the hole before he slide the nipple in.

Herb


----------



## Herb Stoops (Aug 28, 2012)

vchiarelli said:


> @Herb Stoops
> 
> Don't mean to hijack this thread but how did you attach the box to the back of the 4100? Do you have a side view?


Here are the pictures.
Herb


----------



## Daikusan (Apr 12, 2013)

Herb, Thanks for the pictures


----------



## furboo (Oct 12, 2015)

Yes, very nice, Herb. Do you think it would help to close off the bottom of the saw cavity?


----------



## Herb Stoops (Aug 28, 2012)

furboo said:


> Yes, very nice, Herb. Do you think it would help to close off the bottom of the saw cavity?


Yes, The base cabinet it sets on has a flat top, but if any gaps along the bottom of the saw allow air to feed the airflow. A 6' duct requires a lot of air,and all the openings under the saw table help with the air flow, This also helps with the dust collection not allowing stray sawdust from escaping.
On my router table I have a makeup air opening in the side of the box under the table to add more air for better air flow. You have already found that if you choke down the DC it drastically cuts the air flow.

The biggest mistake that is made is that dust collectors are assumed to be like vacuum cleaners, and they are NOT.
Vacuum cleaners work on high velocity ,low volume. Dust collectors operate on large volume of air and lower velocity. 
So if the volume is choked down the air flow is basically shut off.
Herb
To address your question ,Jeff on your saw,it is on the moble base and made for the "bag" that attaches to the bottom of the saw. You might have to find a way to close the bottom.
Herb


----------



## woodknots (Mar 7, 2012)

Herb - very ingenious. As you probably know, I just bought a 4100 and plan to take it off the gravity rise and put it on a new base to lower the height. I like your modification.


----------



## Herb Stoops (Aug 28, 2012)

vchiarelli said:


> Herb - very ingenious. As you probably know, I just bought a 4100 and plan to take it off the gravity rise and put it on a new base to lower the height. I like your modification.


I built the cabinet because the mobile base was too large and took up too much room in the shop. Since I never intended to use it on a job site , I didn't really need it. 
There is a market for those mobile bases out there, just list it and you will sell it pretty fast.
Plus this gives me space under it for accessories.
Herb


----------



## woodknots (Mar 7, 2012)

I've seen your setup in another post - I like it. I'm going to build something similar with storage and incorporate a stand for the Router Workshop router table (I inquired about purchasing the plans from them and they were kind enough to mail me a set free of charge). I'm looking at this type of a setup with some modifications.


----------



## tomp913 (Mar 7, 2014)

Saw this on Pinterest, for those who really want to build their own DC system (hope the picture comes out OK). Checked and it does, to get a larger version, right-click and "Save Picture As" and you should be able to enlarge it.


----------



## furboo (Oct 12, 2015)

I finally got some time to build a cart, with the motor rotated and mounted so that I can put a chip collector underneath. The chip collector will be the yellow barrel in the photo, but it isn't hooked up yet. To hook up the fan outlet to the collector, I got rid of the flex pipe and used a section of 5" stove pipe and HVAC tape. I took measurements right before disassembling the HF DC, and then after getting it all put together on the new cart:

Before: 5 26/32" H2O or 960 CFM
After: 6 11/32" H2O or 1003 CFM

The small increase is because of the shorter outlet-to-collector pipe, plus now there's no 90 degree bend.


----------



## Herb Stoops (Aug 28, 2012)

Cherryville Chuck said:


> I certainly never thought of it as being able to take an accurate reading but it is an excellent way to monitor system and filter performance since you'll obviously take a reading when the system is new and that will allow you to be able to track performance over time and with filter cleanings. Since the set up is static it will respond accurately to changes even though it isn't particularly accurate in terms of absoluteness. That's all I would really be interested in knowing, since there is very little I can do to change the system, is to be able to monitor how well it is performing under it's relatively fixed parameters.


The electrician that hooked mine up put an ammeter on disconnect to monitor the currant flow. This also tells me if the amperage decreases that the airflow has decreased and the filters are getting plugged up. 
Here are a picture of no air flow and another of full air flow.

Herb


----------



## Daikusan (Apr 12, 2013)

Herb, help me out here. 

In my thinking a plugged filter would increase the resistance (air flow here) making a heaver load on the motor. A heaver load would draw more amps. Thus when the air flow decreases the amps go up.

By your readings that is not true. What were you doing to create no air flow, shut all the gates? Full air flow open all the gates?


----------



## furboo (Oct 12, 2015)

I just added the Rikon impeller:

Before: 6 11/32" H2O or 1003 CFM
After: 7 31/32" H2O or 1124 CFM

An improvement, but I have to admit that I'm a bit disappointed. That's only about 10%.


----------



## Daikusan (Apr 12, 2013)

furboo said:


> I just added the Rikon impeller:
> 
> Before: 6 11/32" H2O or 1003 CFM
> After: 7 31/32" H2O or 1124 CFM
> ...


Any chance you took amp measurments before and after?


----------



## furboo (Oct 12, 2015)

Daikusan said:


> Any chance you took amp measurments before and after?


Steve, no, I didn't measure amps. This guy did:

Harbor Freight Rikonstein DC - Product Reviews - Wood Talk Online

He also claims he nearly doubled his CFM. The big difference could be because he's running 5" pipe, whereas I'm still on 4". BTW, I had no trouble ordering the Rikon impeller.


----------



## johnnie_dr (Jan 8, 2016)

FurBoo,

Great documentation on all of your HF DC mods...thanks. As mentioned in an earlier thread, I've explored similar mods with my HF DC, although not quite as extensive as yours. I did consider the impeller swap with a Rikon unit. I too think your CFM numbers (before & after) are disappointing, after all that work and $$.

Regarding the big yellow drum...I'm sure you noticed that the drum has molded hand holds, that were formed during blow-molding of the drum, thus creating cavities on the inside of the drum...meaning, the walls of the drum are not completely smooth where those hand-hold are. I suspected that they may disrupt the flow (vortex) of the incoming air and chips, so I filled the cavities with ridgid foam, then sealed it with the same HVAC you used on your stove pipe connection (between blower and collector) (love that idea...I'll try that too).

The thien baffle I made, to fit the yellow drum, fit just at the internal part of the drum where the sides of the drum angle straight down, which happen to be just below the hand hold cavity. This provides the tightest fit of the baffle too. I also cut and created a small window in the drum to see where the level of sawdust was, as it filled. Just used a 2" hole cutter and epoxied in a small circle of plexiglas.

I too have found, as most of the DC modders, that the shorter the distance, between blower and collector, the better...and the less flex hose used is better. It might seem that the bumpy walls of flex hose is insignificant...but it matters. Just for clarity, my rack system in stationary, not on a cart. I have it attached to my stud walls in a small closet on the back side of my basement shop. It is piped into my overhead 4" PCV main trunk. I then have solid PCV drops down to my main tools (Tbl Saw, jointer, planer, chop saw, etc) At the end of the drops, I have a Blast gate and a short section of flex aluminum pipe (see image attached). It's flexible, yet the ridges are not quite as "bumpy as the flex hose, plus I keep the length to a minimum.

Another key element in this whole thing, is sealing the joints and junctions between all connections. It might seem like a little thing (which count) but I use stretchy sealing tape at all my junctions of the pcv joints and blast gates...and i do see and feel a difference in performance.

Sorry to get so long in my discussion...just wanted to share my trials as you are in yours....hope this helps. And thanks again for sharing your tests.

Johnnie


----------



## Bob Adams (Jul 5, 2014)

furboo said:


> I just added the Rikon impeller:
> 
> Before: 6 11/32" H2O or 1003 CFM
> After: 7 31/32" H2O or 1124 CFM
> ...


That sounds about right. I just threw my notes away, but if my failing memory serves at the Dust Deputy intake mine were:
Before-950
After-1150 (ish)
The largest improvement showed up at the ends my duct runs. I exhaust straight outside so I don't have the back pressure created by a filter, and I used a cheapo anemometer to take my readings.


----------



## Bob Adams (Jul 5, 2014)

furboo said:


> I just added the Rikon impeller:
> 
> Before: 6 11/32" H2O or 1003 CFM
> After: 7 31/32" H2O or 1124 CFM
> ...





furboo said:


> Steve, no, I didn't measure amps. This guy did:
> 
> Harbor Freight Rikonstein DC - Product Reviews - Wood Talk Online
> 
> He also claims he nearly doubled his CFM. The big difference could be because he's running 5" pipe, whereas I'm still on 4". BTW, I had no trouble ordering the Rikon impeller.


Yea you better be careful about that guy......OH WAIT, that's me..>


----------



## furboo (Oct 12, 2015)

Thanks John, good stuff. I had not noticed the handle cavities and will have to address that. The handles are right at about where I would think the level of the Thein baffle would be placed. Not good.

I don't like that the lid on the drum isn't flat. I may cut a round piece of ply to put on top and fill between it and the lid with foam. I plan on using 6" stove pipe between the drum and blower, the pipe has a flange fitting, and I really would like a level surface on the lid to attach the flange. For 6" pipe, I need to offset it from the center of the lid an inch or two, which makes the convex shape of the lid more of an issue.

I need to retire so that I can get some (wood)work done.


----------



## furboo (Oct 12, 2015)

Bob Adams said:


> Yea you better be careful about that guy......OH WAIT, that's me..>


Great to have you here, Bob! It's interesting that your measurements at the DD are similar to mine. I'm taking mine at one side of the original HF wye that's attached to the blower (the wye is going to be removed when I hook up the drum).

It's also good to hear that you got a bigger difference at the tool port. I believe it, but I don't yet understand it.


----------



## Herb Stoops (Aug 28, 2012)

Daikusan said:


> Herb, help me out here.
> 
> In my thinking a plugged filter would increase the resistance (air flow here) making a heaver load on the motor. A heaver load would draw more amps. Thus when the air flow decreases the amps go up.
> 
> By your readings that is not true. What were you doing to create no air flow, shut all the gates? Full air flow open all the gates?


Steve, yes the picture is with all the gates closed and the second with all the gates open at the end of each run of 6" duct,so maximum air flow.


When the motor is giving more air flow it is working harder thus using more amps. Less air flow it uses less amps. because it is not working as hard. If the filters are plugged it has less air flow ,thus less amps.

We tested the system with a pito tube during installation with a 6' piece of 6" duct to establish a benchmark maximum air flow, again with the duct system complete and open ended and closed ended to compare air flows and amp. readings


----------



## Bob Adams (Jul 5, 2014)

Thanks, there are a couple of things I didn't mention. I threw the wye away years ago. I had a ton of leaks around the motor and impellor housing, used silicone calk around the motor and HVAC tape on the impellor. This is my last and final shop, so I put out the extra money for the Nordfab ducting. If the DC gives up the ghost I may replace it with a true cyclone, but my shop size just doesn't warrant anything bigger than a 2hp unit. So far I have been really pleased with the Rikon impellor, for me, any improvement over the stock HF DC helps.


----------



## johnnie_dr (Jan 8, 2016)

Hi Rob,

I do recall you said your yellow tub was "bloated" when you got it (due to altitude), but I thought it came back to normal shape. My lid it nice-n flat?? I initially made a lid and thien baffle outta MDF, not wanting (or trusting myself) to punch 2 big holes in the poly lid. It worked ok, but then I came to my senses and said, gee...the lid that came with it sure would seal better...and used it for the inlet & outlet and baffle.

I don't have any conflicts with my baffle and the tub walls, plus covering the hand hold cavities, should resolve that issue.

Johnnie


----------



## furboo (Oct 12, 2015)

John, so your lid came flat? Yes, I did have a bloating issue, but I was assuming that was just the bottom.

This is starting to sound like a weight loss program.


----------



## Daikusan (Apr 12, 2013)

furboo said:


> Steve, no, I didn't measure amps. This guy did:
> 
> Harbor Freight Rikonstein DC - Product Reviews - Wood Talk Online
> 
> He also claims he nearly doubled his CFM. The big difference could be because he's running 5" pipe, whereas I'm still on 4". BTW, I had no trouble ordering the Rikon impeller.


Thanks Rob,
The link you provided answered one of my questions - the start up amperage. The extra amps may stress the cap but thats easy to change. If it switches of the starter coil quickly it shoulent stress the motor too bad. I still have to figure out how to get the HF to Japan cheaply.


----------



## Daikusan (Apr 12, 2013)

Herb Stoops said:


> Steve, yes the picture is with all the gates closed and the second with all the gates open at the end of each run of 6" duct,so maximum air flow.
> 
> When the motor is giving more air flow it is working harder thus using more amps. Less air flow it uses less amps. because it is not working as hard. If the filters are plugged it has less air flow ,thus less amps.
> 
> We tested the system with a pito tube during installation with a 6' piece of 6" duct to establish a benchmark maximum air flow, again with the duct system complete and open ended and closed ended to compare air flows and amp. readings


Herb, thanks for the explanation

Im still missing something in my logic. When a motor is freewheeling (no load) the amps go down. When you apply a load the amps go up. The larger the load the higher the amps to an extent. 

I guess Im not understanding the air movement in the impeller. It must not work like a box fan. If you put an amp meter on the fan and put a piece of plywood over the suction side the amps go up. I would think the same with the impeller. 

The other question I have is more or less to Bob with the reverse vanes. It still works? Cups increase efficiency compared to straight vanes. I would think the reverse vanes spinning the same direction you would loose efficiency.


----------



## furboo (Oct 12, 2015)

Daikusan said:


> Im still missing something in my logic. When a motor is freewheeling (no load) the amps go down. When you apply a load the amps go up. The larger the load the higher the amps to an extent.


I with you Steve, I'm still not sure about this, either. But here's my guess as to what's going on: The motor tries to keep a constant RPM. If the air forces (and the resulting torque) are higher on the impeller, the motor has to work harder to keep that constant RPM, and so it draws more amps. Those air forces depend on how the impeller was designed. Specifically, at a some value of the CFM (say when the filter is clean), decreasing the CFM may or may not increase the air forces, depending on the impeller design. In Herb's case, the air forces decrease, but I'm not convinced that's true for every impeller, or possibly even Herb's impeller if it was operating at a different clean-filter CFM.


----------



## furboo (Oct 12, 2015)

Herb Stoops said:


> We tested the system with a pito tube during installation with a 6' piece of 6" duct to establish a benchmark maximum air flow, again with the duct system complete and open ended and closed ended to compare air flows and amp. readings


Herb, I'm impressed. The pitot tube is the way to go to get a more accurate CFM than my lazy approach. I'm only measuring the static pressure (the holes on the side of the pitot tube), referenced to the room pressure (instead of the local total pressure). As long as I measure near the pipe opening, the total pressure losses from the room to the measuring point shouldn't be too bad, but it's a big approximation. That's the main reason I've been saying my CFM numbers are approximate.


----------



## Herb Stoops (Aug 28, 2012)

furboo said:


> Herb, I'm impressed. The pitot tube is the way to go to get a more accurate CFM than my lazy approach. I'm only measuring the static pressure (the holes on the side of the pitot tube), referenced to the room pressure (instead of the local total pressure). As long as I measure near the pipe opening, the total pressure losses from the room to the measuring point shouldn't be too bad, but it's a big approximation. That's the main reason I've been saying my CFM numbers are approximate.


What I found interesting was the airflow dropped about 1/3 from the benchmark to the full system with all the ducting,cyclone,filters ,and dust bin connected.
This is where a lot of the manufacturer CFM ratings cause confusion.
Herb


----------



## johnnie_dr (Jan 8, 2016)

Hi Rob,

Here's a quik pic of my tub top...as opposed to muffin-top...

It's not dead-flat, since it is polyethylene and the intrusion of my 3 lag screw that enable me to mount and level my baffle assembly underneath. And the infeed/outfeed pipes. It seals well around the rim where it is level.

But...it's not domed or wonky. ???

John


----------



## furboo (Oct 12, 2015)

johnnie_dr said:


> Hi Rob,
> 
> Here's a quik pic of my tub top...as opposed to muffin-top...
> 
> ...


John, thanks for the pic. I guess mine is domed, muffin-topped, wonky :frown: If I put a straight edge across the top, the lowest point (just short of the rim) is about 3/8" lower. I'm not sure i could make that out in your pic. It sure does seal well. After all, it was able to hold the sea-level pressure when brought to my altitude.

If I push on the center, it does compress in. So I put a heavy tool box on it this morning. Hopefully that will permanently push it back in.


----------



## Lappa (Feb 5, 2015)

Sorry to come in so late on the thread. I'm going through the same procedure with a 2hp second hand unit and have spent some months testing and modifying the system to try and get max. performance.

I've even gone to the expense now of buying a Hotwire anemometer to do accurate flow measurements but I was using a home built Pitot tube arrangement before which is easy to build.

Just a couple of questions:
- when you said you got 6" H2O at the entrance to the impellor, I take it that was with the entrance blocked.
- when you said you got 2.5" H2O at the end of the 4' flex pipe, was that also with it also blocked?

The reason I ask is that if they were both blocked then the readings should be the same - lower readings at the end of the pipe would indicate leaks.
If the end if the 4' pipe was not blocked then the measurement you got is not a very good indication of performance/ CFM.

The first reading at the entrance is used to calculate potential CFM which is what you did. If you then wish to measure actual CFM down the pipe, you need to measure the difference between stagnation pressure and static pressure.
To do this, you need to have one end if the manometer connected to a right angle stagnation pipe in the centre of the pipe (end facing the airflow) and the other end of the manometer connected to a pipe measuring the static pressure at the inside wall of the pipe. In reality a Pitot tube arrangement. I made one out of diesel injector pipes and it measures within 2% of the Hotwire anemometer. That's probably a fluke as all Pitot tubes should be calibrated.

One thing that was mentioned earlier was a current flow (Amps) of your system. That is a very important measurement as you may find that the hp of your motor has been overstated and no matter what's mods you do, improvements will be minimal.

I've done heaps of measurements with and without filters, bag needle felt filters vs pleated filters, system with and without pipes, changing pipe diameters etc. etc.

I'm having problems uploading pics. from the iPad at the moment so I'll try on the computer and if a yones interested I can give some of the readings I've got off my 2hp?? Dusty with various mods.


----------



## Daikusan (Apr 12, 2013)

Lappa said:


> I've done heaps of measurements with and without filters, bag needle felt filters vs pleated filters, system with and without pipes, changing pipe diameters etc. etc.
> 
> I'm having problems uploading pics. from the iPad at the moment so I'll try on the computer and if a yones interested I can give some of the readings I've got off my 2hp?? Dusty with various mods.


I would be interested in seeing your measurment posts and pictures. Most likely others would be too.


----------



## furboo (Oct 12, 2015)

Lappa said:


> Sorry to come in so late on the thread. I'm going through the same procedure with a 2hp second hand unit and have spent some months testing and modifying the system to try and get max. performance.


Welcome Peter! I'm thrilled that you're going through the same process.



> I've even gone to the expense now of buying a Hotwire anemometer to do accurate flow measurements but I was using a home built Pitot tube arrangement before which is easy to build.


You and Herb are making me feel really lame. First a pitot tube, now a hotwire??? Sheesh!!! Are you guys really woodworkers, or my teachers from 30 years ago coming back to heckle me? :smile:

Seriously, I used hotwires once 30 years ago for a contracting job when I was in school, but they were the REALLY thin type with awesome frequency response (for turbulence). The wires and equipment were very expensive. Hopefully, like lots of electronics, they've come down in price. Where did you buy this?



> Just a couple of questions:
> - when you said you got 6" H2O at the entrance to the impellor, I take it that was with the entrance blocked.
> - when you said you got 2.5" H2O at the end of the 4' flex pipe, was that also with it also blocked?


Nothing was blocked, but maybe I don't understand your question. By "entrance to the impeller", I actually meant as close as I could get, which in this case, was with the original HF wye + a small section of flex hose. See the third photo down on the first post of this thread.



> The reason I ask is that if they were both blocked then the readings should be the same - lower readings at the end of the pipe would indicate leaks.
> If the end if the 4' pipe was not blocked then the measurement you got is not a very good indication of performance/ CFM.
> 
> The first reading at the entrance is used to calculate potential CFM which is what you did. If you then wish to measure actual CFM down the pipe, you need to measure the difference between stagnation pressure and static pressure.
> To do this, you need to have one end if the manometer connected to a right angle stagnation pipe in the centre of the pipe (end facing the airflow) and the other end of the manometer connected to a pipe measuring the static pressure at the inside wall of the pipe. In reality a Pitot tube arrangement. I made one out of diesel injector pipes and it measures within 2% of the Hotwire anemometer. That's probably a fluke as all Pitot tubes should be calibrated.


You're absolutely right, ideally, I would measure the stagnation (or total) pressure at the same location as the static pressure, using a pitot tube. Like I said a couple posts back (to Herb), assuming that the room (ambient) pressure is the local total pressure is a big approximation to get the flow rate.

On the other hand, I'm always measuring static pressure at the same location relative to the inlet to the room. So for example, to get the effect of the long 4" hose, in the last photo of the first post, I first hook up the long hose to the wye, THEN I put on the coupler that has the static pressure tube. If I didn't it the other way around, I agree, the comparison change to adding the long hose would be totally wrong.



> One thing that was mentioned earlier was a current flow (Amps) of your system. That is a very important measurement as you may find that the hp of your motor has been overstated and no matter what's mods you do, improvements will be minimal.
> 
> I've done heaps of measurements with and without filters, bag needle felt filters vs pleated filters, system with and without pipes, changing pipe diameters etc. etc.
> 
> I'm having problems uploading pics. from the iPad at the moment so I'll try on the computer and if a yones interested I can give some of the readings I've got off my 2hp?? Dusty with various mods.


I'd love to see your numbers, Peter! You sound like you're much more careful in your measurements. Personally, I wanted to keep all this simple and get reasonable estimates to changes that I made, better than "it seems to be sucking a lot more." But I'm glad there's someone else out there who wants to be a lot more precise. I gave up fluids in the lab a long time ago and now fake it all on the computer :smile:


----------



## coxhaus (Jul 18, 2011)

I think this post is getting good. I think I know you need two 4 inch ports to flow a 6 inch pipe. But how many amps does it take to make the 6 inch pipe work? I know there are lots of variables but is there a rough estimate?

I am trying to make a Baldor 2 HP motor on a Cincinnati 12.25 inch blower straight blade aluminum fan work with 6 inch pipe. 

I can not find 5 inch light weight PVC pipe.


----------



## Lappa (Feb 5, 2015)

Furboo, looking at your picture, I believe you have a Y connection with two 4" outlets, coming off a single 5"?? connection to the impellor housing inlet. One of these 4" inlets is blocked and the other is open with the manometer tube fitted to it. Hopefully that's correct:smile:

The CFM potential of an extraction system will be limited, in one regard, to the size of the pipe you intend to use throughout your system.
To measure the* potential* CFM of a dusty for a given pipe size , one method that is reasonably accurate, is the measure the inches of H20 with the end of the pipe blocked. In Furboo's example, it would be at the entrance to the Y that goes to the dusty with the manometer fitted where it is. Its best done as close to the impellor inlet as possible to minimises errors caused by leaks. Using a formulae from BobL,

Static Pressure Potential Air flow in CFM 
in H20 4" 6"
2" 178 CFM 548
3" 222 CFM 682
4" 260 CFM 794
5" 294 CFM 897
6" 325 CFM 989
7" 354 CFM 1074 
8" 381 CFM 1154
9" 406 CFM 1229
10" 430 CFM 1300
11" 453 CFM 1368
12" 475 CFM 1433 

If you were to just measure the pressure at the inlet to the Y with the pipe not blocked, the figures will be a lot less (see below)

For instance, my system uses 6" pipe and the static pressure with the pipe blocked is 7.25" H2O which, by the above figures, gives me a potential of just over 1074CFM.

I have a measuring point, some 5 metres from the impellor inlet, along a straight section of pipe where I take all my flow measurements. The inlet at the end of this straight section is open for the following measurements.

So, 
- a potential of 1075CFM (using the figures above), 
- Actual 861CFM (measured with an anemometer) 
- using my Pitot system connected to the manometer I get just over 4.5" which is approx. 855CFM 
















However, the static pressure using a manometer (with one end opened to atmosphere) at that same point is 1 5/8" H2O which suggests less than 548CFM. ??

















So having one end open to the atmosphere is not particularly accurate BUT it will give a figure that you can see go up or down depending on changes you make.

The reason I first asked whether you had the pipe blocked for your 6" reading then open at the end of the 4' flex pipe for your 2.25" reading is that the differences for either both open or both blocked is a bit hard to reconcile.

BTW how can I make the pictures smaller on this forum??? mine are HUGE!!


----------



## Daikusan (Apr 12, 2013)

I use photoshop to make mine smaller. I crop it to 5X7 then use the web resolution function to make it smaller. There are other picture editing applications that are much cheaper. Peter, the pictures you put up are fine


----------



## furboo (Oct 12, 2015)

Lappa said:


> Furboo, looking at your picture, I believe you have a Y connection with two 4" outlets, coming off a single 5"??
> connection to the impellor housing inlet. One of these 4" inlets is blocked and the other is open with the manometer tube fitted to it. Hopefully that's correct


Yes, just to be clear, two 4" *inlets*, not outlets.



> Using a formulae from BobL,


I found that formulae, but I can't find where he derived it. Do you have that?



> - a potential of 1075CFM (using the figures above),
> - Actual 861CFM (measured with an anemometer)
> - using my Pitot system connected to the manometer I get just over 4.5" which is approx. 855CFM
> 
> However, the static pressure using a manometer (with one end opened to atmosphere) at that same point is 1 5/8" H2O which suggests less than 548CFM. ??


Doesn't this imply that your stagnation pressure at your pitot tube is higher than the room's stagnation pressure??? I don't see how this is this possible, unless your pitot is downstream of the impeller.

And somehow I'm getting 1653 CFM for 4.5" H20 (at sea level), but I'm notorious for making math mistakes. I'm suspicious that I'm missing a factor of 2 somewhere.



> The reason I first asked whether you had the pipe blocked for your 6" reading then open at the end of the 4' flex pipe for your 2.25" reading is that the differences for either both open or both blocked is a bit hard to reconcile.


Both were open. I think I need to draw a diagram, but tell me more what you're having a hard time reconciling.

Also, great setup! I look forward to more numbers.


----------



## furboo (Oct 12, 2015)

...and Peter, most image viewers will allow you to scale down the image size. I use Preview on the Mac. But also, the size of your pics look fine to me in the Chrome browser, because even if I click on the image, it scales it to my window size. I only see that your images are big if I save the image and open it in Preview.


----------



## coxhaus (Jul 18, 2011)

You can email your pictures to yourself using medium size. Then post the picture from your email.


----------



## Herb Stoops (Aug 28, 2012)

Rob, Originally I had a 2hp motor and a 12" dia. straight blade Granger fan, hooked up to a 6" PVC pipe duct work. I took the original face off the fan unit and replaced it with one with a 6" inlet that I made out of 3/4" BB plywood. I found that if I was restricted anywhere in the system to 4" ,that was all the airflow I would get. When I opened up the inlet to 6" I increased my air flow to max on the fan.I made the new face plate out of BB plywood and cut a hole the size of a 6" coupling O.D. and inserted it into the faceplate and caulked it and angled screws into the plywood from the inside to hold it in place, if you do something like that be sure to bevel or radius the inside of the hole to eliminate turbulence. Later I replaced the motor with a 3hp.
Herb


----------



## Herb Stoops (Aug 28, 2012)

Lappa said:


> Furboo, looking at your picture,
> 
> 
> BTW how can I make the pictures smaller on this forum??? mine are HUGE!!


I right click on picture open in paint, go to resize at the top,open, click on pixels, change top quantity to 800, click OK , save, then you can use in the forum. 

Herb


----------



## Lappa (Feb 5, 2015)

Sorry, meant inlet. 

The term "stagnation pressure" is the term used to describe the pressure at the tip of the pitot tube facing* into* the air stream. The term "static pressure" is the term used for the pressure being measured at the tip of the tube that is connected to the duct wall. This is shown in the diagram I included above. All measurements are taken upstream of the impellor.

So, with the pitot tube tip facing into the air stream, the pressure on that side of the manometer will indeed be greater than the pressure at the duct wall. The difference in pressure is called "velocity pressure" and you can use this to calculate air speed then CFM.









In reference to the photos of the measurements being taken and the manometer reading with the low reading of 1 5/8":
If you look at the photo of the manometer, the left side tube (with the higher level) is the one in the ducting therefore it is reading a lower pressure than the open end (right side tube) which is measuring the pressure in the room. This lower pressure is caused by the air flowing over the end of the tube. I can change the reading by inserting the tube further into the pipe. Near the duct wall the negative pressure is not as great (ie. the difference between the two liquid levels is less) as in the centre (ie. the difference between the two liquid levels is greater).

My point regarding that measurement was to show just that; that inserting a vertical tube from a manometer into a duct with the other manometer end open to the room is not an accurate method for measuring CFM - its only a relevant measurement when you do it in conjunction with a blocked pipe end ie. Maximum static pressure. When measured at the impellor inlet it gives you CFM potential, when measured at the end of a duct and compared to the first one, it shows if there are any leaks.

I regards to my having problems with reconciling your figures is the size of the drop over 4'. Admittedly, I had my system totally connected, but I got 5.5" H2O at 6" from the impellor and 3" H2O at the end of a 21' length of pipe while you got a drop from 6" H2O to 2.5" H2O over 4', which seems very large for such a short distance.

Update
I just carried out two readings 4' apart on my system (its 6"), one at the open end and one 4' in, and the change in readings was only 0.25" H2O


----------



## Lappa (Feb 5, 2015)

This is the story behind my extractor install and modifications. Being in Australia its 240V at 50 Hz.
Bought a second hand generic 2HP extractor with pleated filter. Specs. were 240V, 50 Hz, 7.7A, Single phase, 2950RPM. It had the usual 5" inlet with a Y fitted to give two 4" inlets. Outlet to the separator was 5". Pleated filter on top and plastic bag below. I modified the unit so the separator, filter and bag as an assembly could be easily removed as the extractor was going into a small shed - see my first post.

Since I was considering a long duct run, I knew 4" pipe would be too small and 5" pipe (called pressure pipe over here) is very expensive ($181 for 18 ft) and there are very few variations in fittings available. I decided to run 6" ducting - cheap ($59 for 18') and there are heaps of different fittings available. It will also allow me to upgrade to a 3hp machine later if needed.

Made up a 6" to 5" adaptor to go to the inlet of the dusty and built the system through my shed. At the end of the 21' of ducting there is 6" flexible pipe 8' long going to my table saw. There is one Y fitting off the main duct going to my router table and SCMS (just swap the pipe where needed). Blast gates are installed.

*Start of the modifications.*
I decided to measure the AMPS to get a general idea of how the system was performing. I had no air flow measuring gear at this stage. The result was a miserable 2.8A. I'd expect a 2HP system connected to all the ducting and filters (loaded) to be up around 4 to 4.5A. I removed the ducting from the front of impellor and disconnected the filter pipe from the separator and retested the amps with no ducting or filter - 3.36A.

With the filter off (extractor is in a small shed and removing the filter is the only way I could get in to measure), the Maximum static pressure (inlet blocked) was 175mm H2O (6.89" H2O) which gave it a potential of 1065CFM. I purchased an anemometer and actual CFM at a test point 16' from the impellor (this is were I do all my testing as its a long run and gives minimal turbulence) was approx. 450 CFM with the filter reconnected and the system back to normal.

Stripped the system down so the front was off the impellor housing leaving the impellor naked and the outlet pipe and adaptor removed leaving a 6.5" X 4" rectangular outlet. The system should now be unloaded and should achieve close to the rated AMPS, which for a 2HP system is approx 6A. I got 4.55A. So the motor is not 2HP is about 1.5HP. A bit of research showed that this not uncommon - motors being over rated.


So I decided to go ahead and remove as much restriction from the system as I could to raise the loaded AMPS up from 2.8A closer to the 4.55A (which of course i would never reach) and hopefully raise the CFM.


----------



## furboo (Oct 12, 2015)

Peter, thanks for how to get velocity from Bernoulli's equation. That's what I'm using, so somehow the numbers we plug in are different. But I was more curious about BobL's equations for CFM for 4" and 6" pipes. I found his equations on the web, but it's not clear how he came up with these.



Lappa said:


> In reference to the photos of the measurements being taken and the manometer reading with the low reading of 1 5/8"...


So with the pitot hooked up, you're measuring p_stagnation within the pipe, and not hooked up, you're measuring p_room. That's what I thought. I'm assuming the static pressure in the pipe is the same in both cases. My point was that from your measurements, p_room is quite a bit less than p_stagnation, when I believe it should be more. p_room should be the maximum possible stagnation pressure in the flow, before it gets to the impeller. The reason is that the flow starts in the room at zero velocity (p_room = p_stagnation). Then is makes it's way to the inlet of the dust pickup at the tool and starts flowing down the pipe to the DC, and some point passing by your pitot. Before getting there, losses in the pipe (friction, turbulence) must *decrease* the stagnation pressure (stagnation pressure is related to entropy, and when entropy increases, stag. pressure decreases). Something doesn't make sense.

As long as your static pressure measurement is very close to the start of the pipe, the stagnation pressure loss should be small. My measurement is only about 3" into the inlet. So that's why I don't bother with the pitot tube. But I can't verify how bad this assumption is without building a pitot tube. Right now, I'd rather get to woodworking :wink: But as long as I'm always measuring the static pressure at the same location (3" from the room inlet), relative changes give me some estimate increase and decrease in performance.



> I regards to my having problems with reconciling your figures is the size of the drop over 4'. Admittedly, I had my system totally connected, but I got 5.5" H2O at 6" from the impellor and 3" H2O at the end of a 21' length of pipe while you got a drop from 6" H2O to 2.5" H2O over 4', which seems very large for such a short distance.
> 
> Update
> I just carried out two readings 4' apart on my system (its 6"), one at the open end and one 4' in, and the change in readings was only 0.25" H2O


Keep in mind that the *effect* of the pipe loss I measured was for the Rockler flexipipe, which is extremely rough and bumpy internally (see last photo of first post). It has the ability to stretch out to over 10', but I measured with it at 4', which is typically its length when hooked up to my saw. I expect it to be a lot worse than, say, smooth PVC of the same length, or even standard flexipipe.

Moreover, again, I measured the static pressure 3" from the hose's inlet to the room, *NOT* after the flow had moved through the 4' of pipe section. That's why I called it the "effect" of the pipe loss. I'm not measuring the pipe loss directly. Again, this is so that I get a consistent measure of the overall system performance, by just measuring static pressure in one location (relative to the room inlet). I'm trying to keep the measurements simple.


----------



## furboo (Oct 12, 2015)

Herb Stoops said:


> Rob, Originally I had a 2hp motor and a 12" dia. straight blade Granger fan, hooked up to a 6" PVC pipe duct work. I took the original face off the fan unit and replaced it with one with a 6" inlet that I made out of 3/4" BB plywood. I found that if I was restricted anywhere in the system to 4" ,that was all the airflow I would get. When I opened up the inlet to 6" I increased my air flow to max on the fan.I made the new face plate out of BB plywood and cut a hole the size of a 6" coupling O.D. and inserted it into the faceplate and caulked it and angled screws into the plywood from the inside to hold it in place, if you do something like that be sure to bevel or radius the inside of the hole to eliminate turbulence. Later I replaced the motor with a 3hp.
> Herb


Thanks Herb, I definitely plan to do something like this. Instead of using plywood, I might try enlarging the existing metal face and see how that goes. I do wish that I had held off upgrading the impeller until I had done this.


----------



## Herb Stoops (Aug 28, 2012)

furboo said:


> Thanks Herb, I definitely plan to do something like this. Instead of using plywood, I might try enlarging the existing metal face and see how that goes. I do wish that I had held off upgrading the impeller until I had done this.


That is a good idea, I had toyed with the same idea and making a metal thimble out of sheetmetal and pop riveting it to the face plate, but tried it with the plywood first to see it it made a difference, and then just went with the plywood.
Herb


----------



## Herb Stoops (Aug 28, 2012)

The first system I built, I set up with the fan sucking directly from the duct then blowing into the cyclone, that meant that all the chips and dust were going through the fan. If I accidentally sucked up a large piece of wood or screw/nail, I could hear a ping when it hit the fan. even sucked up a plastic bag and a finishing rag once, and a small can of 3 and 1 oil. 

The one I have now, is hooked up to suck through the top of the cyclone and blows directly into the filters. This seems to work very well ,nothing goes through the fan but air.

My cousin Paul has a small shop and not enough head room for a cyclone , he has the HF set up with a thein separator and found that it does a great job of catching all the larger particles in the dust bin but the fine dust from his drum sander ends up in the wynn filters. So he uses a dust deputy and a shop vac for his drum sander. (he uses a 6" PVC duct).

Herb


----------



## coxhaus (Jul 18, 2011)

Herb Stoops said:


> Rob, Originally I had a 2hp motor and a 12" dia. straight blade Granger fan, hooked up to a 6" PVC pipe duct work. I took the original face off the fan unit and replaced it with one with a 6" inlet that I made out of 3/4" BB plywood. I found that if I was restricted anywhere in the system to 4" ,that was all the airflow I would get. When I opened up the inlet to 6" I increased my air flow to max on the fan.I made the new face plate out of BB plywood and cut a hole the size of a 6" coupling O.D. and inserted it into the faceplate and caulked it and angled screws into the plywood from the inside to hold it in place, if you do something like that be sure to bevel or radius the inside of the hole to eliminate turbulence. Later I replaced the motor with a 3hp.
> Herb


If you don't change the fan size why change to a bigger motor? Won't the amp draw be the same?


----------



## Herb Stoops (Aug 28, 2012)

coxhaus said:


> If you don't change the fan size why change to a bigger motor? Won't the amp draw be the same?


Lee, I don't really know, I didn't have the ammeter on the 2hp motor.
The 2 hp. motor I lost in the fire , but salvaged the fan and housing, cyclone and was searching for a new motor they wanted $600 for one at the motor shop, and I found this 3hp Baldor new in the box for around $250 plus free shipping on the internet so bought it. I have it hooked to 240v. the same as the original one, with a mag switch and a remote control.
Herb


----------



## coxhaus (Jul 18, 2011)

Fire, that will do it. I am just hoping my 2 HP will work. I don't want to have to run a 3 HP.


----------



## Bob Adams (Jul 5, 2014)

furboo said:


> Thanks Herb, I definitely plan to do something like this. Instead of using plywood, I might try enlarging the existing metal face and see how that goes. I do wish that I had held off upgrading the impeller until I had done this.


I understand the reasoning for increasing the intake to 6" but my question/concern is that without doing the same thing to the exhaust, it might create turbulence within the impellor housing. If that happened I would think any benefit would be lost. Looking at my unit I don't see any "easy" way of increasing the exhaust port diameter. I have no idea if this a valid concern or just me over thinking this....


----------



## Lappa (Feb 5, 2015)

Furboo,
My set-up with the pitot tube is the same as (c) in figure 2. The only difference is the type of manometer used.
All my new air flow measurements are now measured using a Hotwire anemometer and when I did a quick check between my Pitot tube set-up and the anemometer, they were within 2% of each other.
Dwyer were very helpful in explaining the measurements, which were accurate and which were not, what each one measured etc. and providing me with spreadsheets for various pressure and air speed calcs.

https://www.dwyer-inst.com/Products/AirVelocityIntroduction.cfm

BTW. The formulae that BobL provided, as far as I know, is formulated from the graphs on Bill Pentz's site but I may be wrong


----------



## Herb Stoops (Aug 28, 2012)

coxhaus said:


> Fire, that will do it. I am just hoping my 2 HP will work. I don't want to have to run a 3 HP.


Lee the 2hp worked just fine for me, it should work good for your setup. you running on 240v ?
Herb


----------



## furboo (Oct 12, 2015)

Peter, what hot wire are you using?


----------



## furboo (Oct 12, 2015)

Bob Adams said:


> I understand the reasoning for increasing the intake to 6" but my question/concern is that without doing the same thing to the exhaust, it might create turbulence within the impellor housing. If that happened I would think any benefit would be lost. Looking at my unit I don't see any "easy" way of increasing the exhaust port diameter. I have no idea if this a valid concern or just me over thinking this....


Bob, it's not ideal. The 5" exhaust will cause more back pressure than 6", but I'm not sure a 6" intake size will necessarily be worse or better than 5". Another deciding factor for me is this fitting:

https://www.lowes.com/pd/IMPERIAL-6-in-Galvanized-Steel-Airtight-Adhesive-Duct-Take-Off/3307820

which doesn't come in 5" :smile:


----------



## Bob Adams (Jul 5, 2014)

furboo said:


> Bob, it's not ideal. The 5" exhaust will cause more back pressure than 6", but I'm not sure a 6" intake size will necessarily be worse or better than 5". Another deciding factor for me is this fitting:
> 
> https://www.lowes.com/pd/IMPERIAL-6-in-Galvanized-Steel-Airtight-Adhesive-Duct-Take-Off/3307820
> 
> which doesn't come in 5" :smile:


Thanks for the link. If you do this please keep us updated, about the performance. Because I have no problem copying you:grin:


----------



## Lappa (Feb 5, 2015)

I decided to upgrade my dust extractor in steps to see what made a difference either good or bad. I also decided not to destroy any component during modification si I could return the unit back to standard.

Step 1 = upgrade the inlet from 5" to 6" 

Made a new front from ply and added a 6" PVC pipe. routed a radius on the intake









My main concern was that the impellor was 12" but the centre section was reduced in blade size for 5" to match the existing 5" intake. I wasn't sure whether the larger opening would reduce pumping efficiency

Attached this to the impellor housing and ran more tests.

(NB. " H2O stated are conversions from mm H2O)

Maximum static pressure - Before 6.89" H2O, now 7.28" H2O - thats good!!
Current draw with inlet open and filter pipe disconnected - Before 3.36A, now 3.98A - thats good!!
Current draw with inlet connected to main ducting but pipe to filter disconnected. Before 3.30A; now 3.5A - good
Current draw with ducting connected and filter pipe connected. Before 2.78A; now 2.67A - thats Bad!!
CFM before approx. 450 CFM; now 456 CFM - Note. I was now taking readings in a recommended vertical matrix then running through a std, deviation spreadsheet so resulting figures are more accurate. So in reality, no real change in CFM.

All the tests seemed to indicate that while the increase in inlet looked good the restricted outlet was hampering the system.

To test this, I ran CFM tests and Amps tests

1) outlet pipe disconnected from the filter - result was 3.5A and 750 CFM.
2) outlet housing removed to expose large rectangular outlet - result 3.71A and 900 CFM. Further testing seems to have this figure steadily at at approx. 860 CFM 
2) All back together again as normal - result 2.79A and 456 CFM

A this was a 2nd hand unit and the pleated filter was probably 5 years old and looked crusty, I removed it and fitted a needle felt filter that had been conditioned previously.
Results 3.5A and 665 CFM - thats great!!! So one of the problems was blocked filter. 

Hopefully I can raise this figure further by removing the restricted outlet by opening it up from 5" to 6"

I'm halfway there.


----------



## furboo (Oct 12, 2015)

Peter, very interesting and looks really nice. In your first image, is the 6" PVC centered on the impeller axis? On my impeller housing, the current 5" inlet is centered on the impeller axis, which I just noticed is off center a bit from the housing.

Also, how did you attach the PVC to the wood?


----------



## Lappa (Feb 5, 2015)

I took the front cover off the impellor housing and traced it onto the ply. I had marked the top of the housing before removal just in case there were any discrepancies. The new front was marked as well.
I added a 18mm "collar" from the pipe to the front panel, then used liquid nails and screws.


----------



## Lappa (Feb 5, 2015)

My latest step was to add a 6" inlet to the separator. I still have to assemble the system and flow test.









Furboo- reading through the posts I saw a question I didn't answer. The hot wire anemometer is a Testo Smart Probe Thermal Anemometer.


----------



## furboo (Oct 12, 2015)

Lappa said:


> My latest step was to add a 6" inlet to the separator.


Nice! I look forward to the results from this change.


----------



## Herb Stoops (Aug 28, 2012)

A fellow in our WW club used this to go from the cyclone to the filters and it reduced the noise by about 1/3. https://www.lowes.com/pd/IMPERIAL-6-in-x-25-ft-Insulated-Polyester-Flexible-Duct/50401800
So I tried it and my cousin tried it and it does make a significant difference.

Herb


----------



## Lappa (Feb 5, 2015)

System now all assembled and tested.









The flow has gone up from 634 CFM to 733 CFM under my controlled test procedure with filters attached but equipment disconnected - a great result for just increasing the separator inlet from 5" to 6"

With the table saw connected, I still have 638.5 CFM with just over 9 m (30 ft) of ducting and flexy and another 150 CFM from a Super Vac to the overhead blade chute.

All the modifications were well worth the effort.


----------



## Lappa (Feb 5, 2015)

Re the Super Vac spec of 150 CFM - I had the parameters set wrong in the program. Should read 85 CFM.


----------



## furboo (Oct 12, 2015)

Looks great, Peter. I want to make sure that I understand how you did your modifications.

It looks like you made your own outlet to the impeller housing out of PVC, molded square to fit that outlet. You posted a photo of this back on Feb. 25 (according to my local date). That makes sense.

Then it looks like you welded a 6" inlet pipe onto the collector, back on March 21. That photo is a bit confusing, because it looks like the original 5" pipe on the left side, as though there's two pipes going into the collector. Also, in your photo yesterday, it looks like the collector had the 6" pipe all along...it looks original. If it's original, I'm wondering what DC it came from. Is the photo on March 21 actually 2 collectors, one on top of the other, with the 5" inlet collector on the bottom?


----------



## Lappa (Feb 5, 2015)

It's all the same collector but now has two inlets. The 6" pipe on the collector is definately an add on. It's on the opposite side to the 5" so I can return it to normal if required. The 5" is internally blocked off. The guy did a great job welding and I tidied it up with some caulking compound and a coat of paint. If you look at the last picture carefully, you can see the paint on the blue sticker.
It's marvellous the sins a coat of paint can cover��


----------



## comp56 (Mar 30, 2017)

Herb Stoops said:


> A fellow in our WW club used this to go from the cyclone to the filters and it reduced the noise by about 1/3.
> So I tried it and my cousin tried it and it does make a significant difference.
> 
> Herb


wouldn't that lower the velocity for FPM? or is because it is past the blower?


----------



## WoodWiz1 (Aug 3, 2018)

DesertRatTom said:


> Several posts just say order the parts numbers and do not mention the HF unit. It also says to make a phone call. Here's the info again.
> 
> _Rikon - 877-884-5167 - ask for parts, do NOT talk about your HF-DC, state you need an impeller for a 60-200 DC, part #22 for the impeller. Part #26 for a new bolt and part #27 for the "spring washer". You can use the old bolt and washer - I did - but bought the new ones anyway [why you ask - because I am that...]. Total cost for all of it - $120.27 including S&H. Download the Rikon Manual for a 60-200M3R.PDF and check for yourself _


I was told by rikon that the impellers are available in limited stock on their parts website.
rikonparts.com/product/60-200


----------

