# Down the DC Hole... or DC Project Part II



## MAFoElffen (Jun 8, 2012)

Funny how you start putting in a DC system and the costs add up quickly... Mostly in the DC connections and fittings. I probably spent more in fittings, connections, ABS pipe, hoses and misc than I needed to... Probably more than on the DC itself... With lots of fitting left over, because after starting, they didn't workout or fit into the plan.

Before, I used a 2" system with a vacuum that originally was a comercial truck-mount type vacuum mounted in a 35 gallon drum, with the hose set up like a cyclone. This did me well for a while. It had plenty of vacuum pressure and throughput. The flow was probably around 750-850cfm... until the motor's bearings in this old unit went... When it was still working, Before it broke down I would just move the barrel to where I was working and hook it up. My planer had both a 2-1/2" & 4" connector, but was fine on the 2-1/2" connector.

Then I got a new saw, it had a 4" DC port that said it required 1050 cfm... I decided I needed to get a bigger more traditional DC and to install static DC lines with drops. I decided to get a traditional Dust Collector rated at 1100 to do that. I decided to put in a separator to collect to shavings.

I got a great deal on a HF 2HP Dust Collector for about $174. It was on sale, then I got anther 20% off. If was a cylone type, but emptied into a plastic bag and flitered through a cloth bag.

Then I needed to connect it to what I needed to. I first bought an economy HF 4" DC starter kit. I got it by hook and crook using another 20% discount... I figured for the price, how could I go wrong, right? Wrong... I got what I paid for- 2 10' 4" hoses, 1 4" Y, various machine connectors for a contractor saw, and 2 that I'll probably use on one of my router fences. I probably should have spent it on a starter kit from Woodcraft or Rockler. It might have been with things I could have used all. The hoses... well, they are usuable, but they are a bit undersized. You really have to work to get it on a DC fitting. I think they were meant to use with tapered fitting as they won't work with standrd 4" DC fittings.

Then I went and bought black ABS sewer pipe and fittings. Why? because I could go from there to white drain pipe (with available adapters). I could also put in a 4-to-2" tee. A short piece of 2' black ABS pipe... which 2-1/2" hose will just slip over. I thought that maybe with drain pipe, I could put the hose on it, But it is just a little too big...

So I cut 2 thin wedges across from each other, about 2-1/2" long... Heated it up with a heat gun, then shaped it too close the cutouts and created tapered fittings... Help it until it cooled (gloves)... Then 1 layer of duct tape.

The I went to a woodworking supply. Was a 3 hour drive each way. I figured I could hit the store before it's DC sale was over. I figured I could pick up a 10' 4 inch hose, a 10' 2-1/2" hose, a 2-1/2" blast gate, a few ABS DWC to DC adapters, a few 4" ends, etc. Even on sale, it adds up fast. I ended up buying a cyclone lid for 4" connectors. It is sort of an odd diameter, but I can make it work.

Not as fast as the person that arrived there at the same time. He had 2 shopping carts. We were picking through the bins together. Seems he was getting them for his shop. 10HP DC with too much suction. All his machinery was hooked up, with everything open and he still had too much suction... so he figured he'd open up another 15 holes for shop cleanup (15 10' 4" hoses) with all the fittings and adapters to be able to vacuum or clean. "Too much vacuum"... "We" should be so lucky!

Another lesson learned- DC fiitings fit into black ABS pipe. I used short pieces of ABS as nipples to fit DC fittings together. ABS fittings were cheaper than CD fittings. I could have used PVC/ABS multi-media adhesive to put it all together... But since just starting out with it, and not sure I wanted to change it around yet to improve it... I instead used screws and duct tape.

By this time, the hoses from Woodcraft were a pleasure to work with. All the fittings That wouldn't work with the HF hoses, worked just just fine with the new clear helical hoses. For the 2-1/2 inch hoses, I had bought fittings with lugs. They twisted right on and sealed. I thought that I should have done more like that. It was a couple more dollars in cost for those fittings- but definitely much less in my labor and frustration.

Last addition was the seperator. I had bought a Cyclone lid from Woodcraft. It was inexpensive and I figured it would be a good start. It's made to fit on something around 20-1/2" outside diameter. (just the size of a 31 gallon steel trash can) I was going to make a conversion for it to fit on a 55 gallon drum... But darn-it, you know- I went looking at my steel and plastic barrels, I found a 31 gallon can that I had been using for my horses grain, that I wasn't using any more, so... Well, I was surprized. I thought I was going to have to add a Thiel-type of baffle to it, but I don't really see anything coming from it to the DC's collection bag. So, it is staying as is for now. I'll use that as is and see what fines are getting by it... Time will tell. I already looked into an A-35 filter kit for my DC, if needed.

After action- If done again, the only DC fittings I would have bought (At a woodworking supply) would have been the hoses, hose ends, and gates. For the hard pipe itself, I might have gone to an irrigation supply and researched schedule 20 4" pipe and fittings. Box store have scedule 40 PVC, but no fittings in stock for them. Schedule 20 PVC might have been cheaper than ABS... But getting ABS from an irrigation would have been cheaper than a box store also. The other fittings I have here now... well, they may just sit here to collect dust (for the what if's) or I'll find a way to return them.

I think my next task is to look for and seal leaks. It's collecting... But is has a lot less suction than I'd expect from a 2HP system. Not really sure whats going on. Maybe my gates are letting too much by them? Thought I would cap off the line past the gates that are not being used and keep them... or seal off all the joints... something. The lid on the separator is foam... maybe replacing with a dense rubber foam seal(?)

If I block the hose, I can see the separator lid compress down on the can... but still, it doesn't seem like it's much. Maybe I was just spoiled by that commercial truck-mount wet-dry vacuum that would collapse a steel barrel if you weren't careful.


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## Bradleytavares (Feb 25, 2012)

Yep, the dollar bills seem to grow wings when setting up a DC system. All my fittings are from Rockler and fit well, purchased the Dustright fittings and hose. Also have the HF DC, rated at 1560 cfm, sure keeps my shop clean. I use the removable fittings and move my collection hose from tool to tool since it's only me in the shop.


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## billyjim (Feb 11, 2012)

That would be a great story if you were writing novels but you are not. Hope someone else can learn from your experience.


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## bigrigger61 (Jan 24, 2012)

*DC woes*

Had to laugh, having gone thru the same problems a year ago. Seems like Rockler, Woodcraft, and Peachtree all have different measurements for 2.5 and 4 inch! Pick one, it being the idea of "proprietary", to either keep you, or run you off.And yes, for simple Chinese plastic, the dollars seem to just float away!


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## Cherryville Chuck (Sep 28, 2010)

MAFoElffen said:


> Another lesson learned- DC fiitings fit into black ABS pipe. I used short pieces of ABS as nipples to fit DC fittings together. ABS fittings were cheaper than CD fittings. I could have used PVC/ABS multi-media adhesive to put it all together... But since just starting out with it, and not sure I wanted to change it around yet to improve it... I instead used screws and duct tape.
> 
> I think my next task is to look for and seal leaks. It's collecting... But is has a lot less suction than I'd expect from a 2HP system. Not really sure whats going on. Maybe my gates are letting too much by them? Thought I would cap off the line past the gates that are not being used and keep them... or seal off all the joints... something. The lid on the separator is foam... maybe replacing with a dense rubber foam seal(?)
> 
> If I block the hose, I can see the separator lid compress down on the can... but still, it doesn't seem like it's much. Maybe I was just spoiled by that commercial truck-mount wet-dry vacuum that would collapse a steel barrel if you weren't careful.



My advice is don't glue all of your pipe together. If you get a plug in the line you won't be able to clear it easily. (Think about those long slivers that fall into the TS cabinet when you are taking thin slices off a board). My advice is to tape the connections together, at least where long runs meet a connector. 

That sounds similar to what my 2HP does. Just because they move a lot of air doesn't mean they can produce a strong vacuum. I think that the impeller is in the airstream so it is probably designed with ample clearance with the sides of the housing which would prevent it from drawing a strong vacuum, which might be just as well since that could cause a lot of parts failures.


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## Jerry Bowen (Jun 25, 2011)

First of all, I don't mind the lenghy writing or thread that is similar to a novel. I can skim or read, my option.

When I realized that I needed a DC system I checked with Rockler and found a price but didn't understand all that was needed to make the system work so I ended up spending about three times what I the intial cost of the system was listed for.

The vacuum from the system is not nearly what I thought it should be, but it does a pretty darn good job at what I whated a DC to do for me. By the way, the only short comings was that the system didn't have enough power to handle the sawdust from the TS, that was until a member of this forum suggested that I drill some half inch holes in the insert to let the air flow to work and now even the DC works just fine on the TS too.


I can't imagine not having the system now. 

Jerry


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## Cherryville Chuck (Sep 28, 2010)

Jerry Bowen said:


> By the way, the only short comings was that the system didn't have enough power to handle the sawdust from the TS, that was until a member of this forum suggested that I drill some half inch holes in the insert to let the air flow to work and now even the DC works just fine on the TS too.
> 
> 
> I can't imagine not having the system now.
> ...


I'm going to have to give that idea a try. Easy enough to do in a homemade insert. How many holes did you drill Jerry?


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## MAFoElffen (Jun 8, 2012)

As I remember, Jerry attached a picture after he did that... Here it is:








Yes... It's enough to catch everything from my saw, but pieces stay in the uprights. If I'm vacuuming/cleaning up the shop, I'll let it run a few minutes before shutting it down... But find pieces sitting on top the gates.

Surprisingly, I was looking up specs on that truck-mount (got bearings for it today) Which has a lot more vacuum pressure, but I was surprised to find that it only has a 165 cfm It has a lot tighter clearances and a 2-stage impeller. I choked at the replacement cost for that motor ($260). But that thing is commercial rated to clean 4000sq/ft. That's the one that will collapse a steel barrel. 

I guess I was used to that and now comparing to the new one, which is sort of like comparing apples to oranges. The old system the vacuum was at the end of separators and filters. No risk of anything getting caught in the impellers, so tighter clearances. Since the DC was made for stuff to get by the impellers... like mentioned, not as tight of clearances, so not as much vacuum pressure. 

You would think them would coincide with each other, but you all are saying not?

One thing I do notice on the new saw... I hate the overhead crown guard. With the DC on the saw, I have that line coming down the wall, on the floor behind the saw. With the overhead crown, the 2-1/2" hose is "y'ed" right after the gate from the same 4" line, run from the ceiling, down to the overhead crown. The overhead crown connection has "bracing" inside it, (sort of a webbing,) so you can't do a standard DC adapter. The OD size is the same OD size as a 2-1/2 end connector so you have to use a union to hook it up... Then with the weight of the hoses and connectors, it has a tendency to flex the overhead crown and the riving knife, one way or another. I'm worried that besides the flexing of the riving knife dragging on the stock, that the blade is going to contact the blade... though it hasn't yet. I'm thinking safety and accuracy wise, I don't like nor feel comfortable with what is going on with that.


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## MAFoElffen (Jun 8, 2012)

Update on the old vacuum motor. It has 3 impellers in a 2-stage. Bearings were $24 for both. Just got it back together and it is louder than ever from the exhaust with the motor now turning at full rpm. I was thinking of videoing it so you could get an idea just how loud that thing is... but no way to directly post videos here.

Figure I could use that for shop cleanup... and maybe plug it into a 2-1/2" port of my dc system and use that to check for leaks. That thing has so much suction I think it could suck up a bowling ball. Leaks might be more apparent with that. Of course if I pluged it in after the separator... Who knows.


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## Cherryville Chuck (Sep 28, 2010)

MAFoElffen said:


> Then with the weight of the hoses and connectors, it has a tendency to flex the overhead crown and the riving knife, one way or another. I'm worried that besides the flexing of the riving knife dragging on the stock, that the blade is going to contact the blade... though it hasn't yet. I'm thinking safety and accuracy wise, I don't like nor feel comfortable with what is going on with that.


Does it vary which side it pulls to or it is always to the same side? I am wondering if you tie a few straps to it from the ceiling so that you can neutralize the torque. I'm like you. I would be concerned about the long term effects of that.


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## DesertRatTom (Jul 3, 2012)

I've had the same kind of experience with my dust collection systems (I have 2) Most of the stuff that works is from Rockler. I have the HF blower and find it really doesn't produce the kind of suction I expected it to. The problem appears to be that the impeller is a very loose fit in the housing (probably to allow material to pass by. But if the blower is at the very end of the system with a chip separator between it and the machine, there is no need for this space. I have a 1hp in my shop that should be less effective, but works fine. The HF is in the garage with the jointer and planer and it really doesn't work all that well. I'm going to check the Rockler unit out although its about $40 bucks more than the HF unit. Will wait for a big coupon first. The lack of size standards is unacceptable. Since when is 4 inches NOT 4 inches? Had no one ever heard of marking things OD and ID? 

Chinese engineering is a joke. Only a couple of companies make it work and that's because they have American personnel in the factory supervising production output and the use of materials. But as a throat cancer survivor, I take dust collection very seriously. 

The best thing so far has been using a battery powered, fan ventilated dust mask (got it from Rockler). It puts filtered air under positive pressure in the mask which keeps dust out. I keep a couple of rechargable battery sets charged so I can keep the mask running for some time after finishing a cut. It also leaks a little air that clears my glasses. Also made a hanging fan in a box with a filter that gradually pulls all airborne dust out of the air.


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## MAFoElffen (Jun 8, 2012)

Dan-

Thanks. Great idea.Most of the time it leans towards the right / towards the wall where to hose comes from. I have it coming from a wall, out on top of a high 32" deep shelf, then from there out to the saw. So down at a steep angle, but still not a straight shot down.. 

If I brace the ceiling above the saw (will have to do that for a suspend crown anyways), then make a rod to mount from that (directly over the blade) with a removable stop at the end... Then put shower ring type rings on the hose... Then it would keep it straight above it, but allow it to raise and lower, still supported straight down.

That should work great for now, until... I have the right side table extension against a wall, with a small freezer behind it. Hey, It's 53" out. That way, most of my work is from the left on the slider. And so I walk between the extension table of the slider and the sun bed. 

If I have to breakdown sheets though, then I need to move it left away from that wall. I know, 1100 pound saw, but it moves pretty well with my pallet jack and later the mobility kit that is still on that cruise ship tour with all my other parts... So it is sort of portable. (LOL) Then I would have to either move the hose and mount left temporarily or do without the dc for that short period... But I'm going to run into that if I build a suspend crown also.


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## MAFoElffen (Jun 8, 2012)

DesertRatTom said:


> I have the HF blower and find it really doesn't produce the kind of suction I expected it to. The problem appears to be that the impeller is a very loose fit in the housing (probably to allow material to pass by. But if the blower is at the very end of the system with a chip separator between it and the machine, there is no need for this space. I have a 1hp in my shop that should be less effective, but works fine. The HF is in the garage with the jointer and planer and it really doesn't work all that well.


I was thinking (dangerous).. Then I started looking into it... Jet Impeller 12" P/N AB411059... fits into the HF housing. The hub diameter needs to be enlarged slightly from 0.75" to 20mm (0.787402"). Just fits in the housing. Increases volume but also increases load about 20-30%. HF used to say that their impeller in theirs was 12". Really only 9.75" Cost is about $110 with shipping. Closer clearances would be okay as I have a separator and there is a grate in the line coming in. Besides the original is a plastic impeller and this one is steel. I looked through the pictures, and theres actually still a lot of clearance in the housing with that impeller. It's just a tight fit getting it through the side plate. That impeller is designed to be driven by a 2HP motor on a Delta DC-1200.

While doing that research, found an interesting tidbit about the differences in DC's and the type my other vacuum falls into. DC's of the type I have, at best pull about 6-7 inches of vacuum. 2 stage vacuums of the type I have (my old one) pull 95-120 inches of vacuum.


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## Jerry Bowen (Jun 25, 2011)

Cherryville Chuck said:


> I'm going to have to give that idea a try. Easy enough to do in a homemfie insert. How many holes did you drill Jerry?


Charles,

I drilled six half inch holes just about an inch to the right of the blade. At first I was afraid that the air flow would still be restricted when the entire insert was covered during a cut, but apparently the dust is sucked into the DC as soon as the cut is finished, this is due, I suspect, is because the sawdust from the cut is relative small and can be pulled in. If build up had been allowed, this would just add to the build up, but when the floor of the cabinet is kept clean, ithe dust just doesn't build up. I should add, the there some build up on the sides of the actual actual air flow, hope you try it and that it work as well for you as it does for me.


Jerry


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## Cherryville Chuck (Sep 28, 2010)

MAFoElffen said:


> While doing that research, found an interesting tidbit about the differences in DC's and the type my other vacuum falls into. DC's of the type I have, at best pull about 6-7 inches of vacuum. 2 stage vacuums of the type I have (my old one) pull 95-120 inches of vacuum.


You were right, you weren't comparing apples to apples if one can draw 15 times harder than the other. Obviously the DC is trying to float the dust on a air column.


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## Cherryville Chuck (Sep 28, 2010)

Jerry Bowen said:


> Charles,
> 
> I drilled six half inch holes just about an inch to the right of the blade. At first I was afraid that the air flow would still be restricted when the entire insert was covered during a cut, but apparently the dust is sucked into the DC as soon as the cut is finished, this is due, I suspect, is because the sawdust from the cut is relative small and can be pulled in. If build up had been allowed, this would just add to the build up, but when the floor of the cabinet is kept clean, ithe dust just doesn't build up. I should add, the there some build up on the sides of the actual actual air flow, hope you try it and that it work as well for you as it does for me.
> 
> ...


I will be giving that a try when I get back home to BC later this summer where the unisaw is. I would have thought that there were enough holes in the cabinet already but that might not be the case or they are just in the wrong spots. Maybe now that dust is such a big issue and other safety items like riving knives are also the manufacturers will start putting a little more engineering effort into things like that.


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## Dmeadows (Jun 28, 2011)

Cherryville Chuck said:


> I will be giving that a try when I get back home to BC later this summer where the unisaw is. I would have thought that there were enough holes in the cabinet already but that might not be the case or they are just in the wrong spots. Maybe now that dust is such a big issue and other safety items like riving knives are also the manufacturers will start putting a little more engineering effort into things like that.


Well. I gave it a try. Drilled 7 3/4" hole about 3/8 from the blade slot. I can see no difference between the modified ZCI, and unmodified ZCI, or for that matter no DC at all, as far as dust above the table, or thrown at me is concerned!

I'll have to post some pictures later. As far as I can tell, the only way to pick up the dust above the table is with an overhead blade guard with DC!


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## MAFoElffen (Jun 8, 2012)

I've been cutting consistently with this new saw and DC for a week and I have big troubles with DC. I really need to change something or I'm going to quickly run into problems. I wish I still had my old carburetor flow gauge so I could test things and have some kind of reference.

The main 4" line goes through the back of the cabinet as 5", to a 4 inside hose, to the blade box, which is just like a funnel around the main and scoring blades. That box raises and lowers when you raise and lower the blade... So when you have the blade set for cutting 3/4" material, the open top of the box is about 5" below the bottom of the table.

Next, big arched opening for the blade height mechanism, about 3" wide arched slot. Then the access panel is louvered. Then, the bottom of the cabinet is open.

So, with not much suction, there's no way it's going to underpressure the cabinet. I don't think there's enough suction to draw the dust from the blade box, so it's still throwing sawdust all over inside the cabinet... all over the mechanisms and in the slide. It's hardly enough suction to suck sawdust off the floor with a 2-1/2" hose!!! 

I think with the two motors, I need to keep the airflow for them... I could make a bottom for the cabinet and there would still be other areas that air would get through. I already suspect that the DC itself is too weak. So, I think I should start by hot-rodding the DC by upgrading the impeller. 

Anyone with ideas how I could measure things to get a baseline, see if there is an improvement... I also think I should check amperage loads, etc, before and after?


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## Dmeadows (Jun 28, 2011)

Well, Mike, there is always the old small tube with water in it trick. Won't give you an accurate measure of anything, but will tell you if you have any improvement. By all means you do want to check motor current to be sure you don't exceed the motor rating.

The saw's main dust port is 5"? That would need at least 2HP DC.. more is better.


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## MAFoElffen (Jun 8, 2012)

Dmeadows said:


> Well, Mike, there is always the old small tube with water in it trick. Won't give you an accurate measure of anything, but will tell you if you have any improvement. By all means you do want to check motor current to be sure you don't exceed the motor rating.
> 
> The saw's main dust port is 5"? That would need at least 2HP DC.. more is better.


I'm trying to remember back... Inductive amp meter. Directions long gone. They're supposed to go around just one line lead right? Cause without disassembling anything, if I put it around the power cord, which contains line, neutral and ground, I get 0.5 amps. That can't be right.

EDIT-- Okay. Pulled the switch. Around just the line lead. Pegs the 30 amp range on start and it's only on a 20 amp circuit(?). It's not tripping the breaker, so I don't know that the meter is reading that right. After it starts, it's only pulling 6.2 amps.

By my calcs with that other impeller, it may pull 7.44 to 8.06 amps once started. Well within that 14.5 amp rating there, but... I guess the deal breaker is going to be how much amps it takes to get it started. (If it throws the breaker trying to start.) That motor is 2HP, but it's Chinese and it's only 110 volt... not 110v/240v. Otherwise, then I would hook it up as 240v.


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## Cherryville Chuck (Sep 28, 2010)

The starting load wouldn't change much unless the new impeller is much heavier I would think. Moving more air at higher pressure should. I think mine was only wired for 240.


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## david_de (Jun 3, 2013)

The tubes of water should give a good reading. If I remember right 2 inches of water is equal to one inch mercury. Have to figure in the barometric pressure too I suppose if there is long period of time between readings.

The guy at woodgears dot ca did some experiments with DC and as I recall he had to slow the intake air as it was coming in too fast. It was moving so much air it was slowing the motor causing less air flow. It was interesting. Probably be able to Google it pretty easy. Here is the link woodgears.ca/dust_collector/blower.html you will probably have to copy and paste not being an old timer (10 posts) I do not think it will let me post a url.


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## Dmeadows (Jun 28, 2011)

MAFoElffen said:


> I'm trying to remember back... Inductive amp meter. Directions long gone. They're supposed to go around just one line lead right? Cause without disassembling anything, if I put it around the power cord, which contains line, neutral and ground, I get 0.5 amps. That can't be right.
> 
> EDIT-- Okay. Pulled the switch. Around just the line lead. Pegs the 30 amp range on start and it's only on a 20 amp circuit(?). It's not tripping the breaker, so I don't know that the meter is reading that right. After it starts, it's only pulling 6.2 amps.
> 
> By my calcs with that other impeller, it may pull 7.44 to 8.06 amps once started. Well within that 14.5 amp rating there, but... I guess the deal breaker is going to be how much amps it takes to get it started. (If it throws the breaker trying to start.) That motor is 2HP, but it's Chinese and it's only 110 volt... not 110v/240v. Otherwise, then I would hook it up as 240v.


Don't worry about the start amps... the wiring and the breaker will handle it. the breaker is time delay. High surge current on start is normal. Uncharged the start cap is essentially a short circuit, so start surge is limited basically by DC resistance of the motor winding(an that is very, very low).


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## MAFoElffen (Jun 8, 2012)

Dmeadows said:


> Don't worry about the start amps... the wiring and the breaker will handle it. the breaker is time delay. High surge current on start is normal. Uncharged the start cap is essentially a short circuit, so start surge is limited basically by DC resistance of the motor winding(an that is very, very low).


Ordered the impeller from ereplacementparts.com... 7-14 days before they say it leaves there. But ordered.

I guess after that would be to look at resistance "after" the blower. (Wynfilter and the "pipe" between the blower and the filter ring.)

...Of course I just watched a video where someone hooked 2 HF 2HP blowers together in series after a cyclone, with a flow regulator, to try to create a 2-stage blower. It sounded like they were afraid things could get out of control...


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## Cherryville Chuck (Sep 28, 2010)

I think he might have been overly optimistic regarding the results. If one is a piece of crap then 2 of them is probably just going to be 2 pieces of crap. Neither unit is capable of building any vacuum and I suspect that the gains in flow won't be anywhere close to 2 times 1 unit. (Imagine 2 washing machine discharge pumps in line. The washing machine pumps and the impellers we have are fairly similar in design and operation.)

Just out of curiosity Mike, what were the claims about extra vacuum and flow for the new impeller? Did the manufacturer make any claims about improved efficiency in dust control?


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## MAFoElffen (Jun 8, 2012)

Cherryville Chuck said:


> I think he might have been overly optimistic regarding the results. If one is a piece of crap then 2 of them is probably just going to be 2 pieces of crap. Neither unit is capable of building any vacuum and I suspect that the gains in flow won't be anywhere close to 2 times 1 unit. (Imagine 2 washing machine discharge pumps in line. The washing machine pumps and the impellers we have are fairly similar in design and operation.)
> 
> Just out of curiosity Mike, what were the claims about extra vacuum and flow for the new impeller? Did the manufacturer make any claims about improved efficiency in dust control?


Yes, I would think same throughput...

Where did I hear about going to a bigger impeller? 

First was a study on dust collectors and their impellers 0n Bill Pentz's site (Bill's Cyclone Dust Collection Research - Home). Funny about that read was that he found that some brands, even though they had different size motors, had the same impellers turning the same rpm in the same housings... But their manufacturers had them rated at different airflows. It also went over impeller design (material handling radial, airfoil & centrifigal) and in making your own blower housings and cyclone separators... He said (if your building your own) that a 2HP motor will drive a 14" material handling impeller. But my housing will only handle a 12" max. He did list the impeller PN's for different sized Jet impellers.

Second was a thread on SawMillCreek:
Larger Harbor Freight Impeller
Where that person did put a Jet 12" impeller in to his HF 2HP DC.

On LumberJocks, they went off in a different direction and config all together. 31 gallon trash can. MDF with layers of mdf on top- trash can rim mortised with weatherstripping to seal it to the rim. Top mortised for the rim of the DC Bag ring housing... Cut into those, inside those, a thiel cutout. Inside the ring housing, the inlet extended in a little with homemade dusting. Top of the DC Bag ring housing, more layers of mdf, mortised to seal onto ring and a 5 inch hole cut into the center. Blower housing inlet through that hole.

So vacuum tubing goes to the inlet on the DC bag housing. Shavings get separated inside that housing by the thiel effect, down to the can. Vacuum supplied by the blower housing... But the exhaust they were venting outside, by connection the blower exhaust to tubing. I didn't see a way to filter fines with that setup... Unless you built a separate filter box... with a filter above and a fines collection reservoir below.

Then there common kinds of mods. Seems to make sense to go to a finer micro filter bag... But with a filter conversion, you get a finer filtering with much less resistance. So you can get more throughput because there is less backpressure beyond the blower (much more filtration area). 

When i was looking at exploded views of various brands and models of DC's. every once in a while I would happen upon a DC that looked similar to mine, except it had hard smooth ducting between the DC blower housing and the DC bag ring housing. I was wondering the why of that. Well it turned out that I happened upon someone's HF DC mod thread, where some used hard ducting to convert their HF DC and they said that mod improved how their's worked... They also explained that manufacturers made that same kind of mod to improve flow.


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## Cherryville Chuck (Sep 28, 2010)

Mike, looked at the links but nothing scientific there. Just a note, the hose from the DC to the bags is positive pressure. 

Fine Woodworking has done a few articles on DC in the last 1 1/2 years or so. Their conclusion is that there must be a cyclone and prliminary filtration between the machine and the DC, preferably with HEPA filtration at the end of the process. Not necessarilary easy to do but something we all need to strive for.


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## MAFoElffen (Jun 8, 2012)

Cherryville Chuck said:


> Mike, looked at the links but nothing scientific there. Just a note, the hose from the DC to the bags is positive pressure.
> 
> Fine Woodworking has done a few articles on DC in the last 1 1/2 years or so. Their conclusion is that there must be a cyclone and prliminary filtration between the machine and the DC, preferably with HEPA filtration at the end of the process. Not necessarilary easy to do but something we all need to strive for.


The DC itself in the DC bag ring housing is a cyclone. I have another cyclone inline before the DC, to remove chips/sawdust before the cyclone...

I have some experience with mechanics and a little bit with physics. Maybe someone with more mechanical physics experience like Otis could jump in to this, but... Building race motors, the first thing we did it, before anything else was to open up the exhaust flow. Something cannot take in more flow if the positive flow (exhaust) is backed up. You do that, before you build pressure in the motor, then remove resistance on the negative side. (But in the case of mine, it it a 12" blower housing with a 9" impeller. Hello...)

That is why the Lumberjocks design works better. The cyclone (and everything) was moved to before the blower, with no resistance after it. It is not attractive to me without any filtration for fines.

Not that vacuum pressure is ever going to be very high with that type and design of impeller... Vacuum pressure cannot be that high with a housing originally designed for a 12" impeller, where they put in a 9.75" impeller. Clearances are just a bit wide. With a 12" impeller the clearances would be narrower... The Jet, with that impeller is rated at moving 1200 cfm. I know those ratings are inflated and lies. But I do expect around 850 cfm and 7-8 inches. That's still not the 130 inches of vacuum that I'm used to with my other vacuum, but a different type of impeller, 2-stage instead of single stage material handling..

If I could fit a 14" impeller in that housing, I would. But then again, I used to build V-8 Vega's and Pinto's.. 426 Hemi 240Z's. I'm sure the clearances would be closer together, thus the vacuum higher... but just not possible in that housing. ...Well, not without cutting the housing opening bigger and making a new cover. Well actually, I did think about adding a "fan shroud" that would instantly shoot the vacuum pressure up... but it would not be in practice a material handling impeller anymore... and it anything ever got through...

So yes... This is where I see my start to solving my problem with this. My saw needs 1050 cfm of dc flow. They weren't kidding. Those numbers were not fudged nor inflated like the DC manufacturers were. I just need to provide adequate dc flow to it or it is going to be gummed up fast. This is not were someone "wishes" they had more flow. I had a requirement that's not being met. I tried and it's not working for me. Either I make this work or I sell this system and have to spend more to find something that fits my needs and requirements. I'm trying to make this work, as the alternatives in a difference class of dc system are much more money.


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## Cherryville Chuck (Sep 28, 2010)

A 12" housing with a 9+ inch impeller. My washing discharge pump analogy was more accurate than I thought it would be. No wonder it won't produce much vacuum. As long as you have a cyclone in line you shouldn't have to worry about clearance.


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## Dmeadows (Jun 28, 2011)

MAFoElffen said:


> Not that vacuum pressure is ever going to be very high with that type and design of impeller... Vacuum pressure cannot be that high with a housing originally designed for a 12" impeller, where they put in a 9.75" impeller. Clearances are just a bit wide. With a 12" impeller the clearances would be narrower... The Jet, with that impeller is rated at moving 1200 cfm. I know those ratings are inflated and lies. But I do expect around 850 cfm and 7-8 inches. That's still not the 130 inches of vacuum that I'm used to with my other vacuum, but a different type of impeller, 2-stage instead of single stage material handling..


Well, 130 inches of vacuum is nice for pulling dirt out of a carpet(relatively low CFM!).

High CFM is needed to capture air born dust and keep it air born till filtered. Don't need high vacuum there! Just enough air moving fast enough to keep the dust airborne!

May not be much of an issue for you, Mike(not familiar with your climate) but venting outdoors also pulls out a lot of heated or air conditioned air! Just sayin...


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## MAFoElffen (Jun 8, 2012)

*Project done/problem solved*

UPS came today with the new impeller. 12" compared to 10". 2" bigger than was in mine. (attached picture) What surprised me. was that others with that HF DC said theirs was 9-3/4 and plastic... Mine was 10" and steel. They must have gone back to a steel impeller. 

Had to take the impeller off it's hub. Mine has a 20mm shaft. The Delta I ordered from was 3/4" (19mm). Drilled it out to 25/32", then reamed out from there to 20mm. Cut the keyway to fit the extra diameter.

Impeller went right in, albeit about 1/4" clearance going through the hole. Fit in there nice. (Attached picture)

Started fine. Took longer to spin up and spin down. Has a deeper roar, like now a V-8, compared to before a 4-cyl. Definitely moving a whole lot more air and for the first time has the feeling of suction to me. I am very happy with the mod. Proof will be when I cut some stock on my saw- if it clears the blade box okay.

Wahoo!!!!


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## Bradleytavares (Feb 25, 2012)

I have a HF DC, 1560 cfm and it really sucks. Maybe it's because it's still sorta new. Is yours the same cfm?


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## MAFoElffen (Jun 8, 2012)

Bradleytavares said:


> I have a HF DC, 1560 cfm and it really sucks. Maybe it's because it's still sorta new. Is yours the same cfm?


The new HF Industrial 2HP, 5 micron DC? Yes. Mine was less than 1 month old. You are right, it sucked in one respect. In functionality, mine wasn't sucking hard enough. It wasn't working out for me. And I needed at least a rating of 1150 cfm for my sliding table saw. The saw manufacturer didn't sluff any numbers on what it required. But HF sure lied on that DC being rated at 1550 CFM... There is just no fricking way. I doubt it was pulling 500cfm.

After the impeller mod I did, I think it's a lot closer. At least it moves a heck of a whole lot more air.


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## Bradleytavares (Feb 25, 2012)

I'll keep your info in mind, but mine still is sucking enough to keep my Delta Contractors saw clear as well as the other machinery.


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## Cherryville Chuck (Sep 28, 2010)

Do you think the motor is handling the extra load okay? That impeller looks a little beefier than the old one besides appearing to cover twice as much area.


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## Dmeadows (Jun 28, 2011)

Cherryville Chuck said:


> Do you think the motor is handling the extra load okay? That impeller looks a little beefier than the old one besides appearing to cover twice as much area.


As long as it does not exceed nameplate Amp rating or exceed maximum ambient operating temp(40 deg C or 104 deg F typical) should be ok. Mike?


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## MAFoElffen (Jun 8, 2012)

Seems okay. Have some time now. Too hot to do much else. I'll pull the switch box and recheck the amp draw. Rated is 14 amp and looked at the older post where I checked it before the mod-- Is was pulling 6.2 amps. 

Now pulling 8.4 amps on the same wire. (Rated at 14 amps.)

I do notice now though with that longer startup/slower spinup... that if the freezer is on (cycling) while the Dust Collector is trying to start, It sometimes will trip the 15 amp breaker. I have 12 gauge 3 wired on that circuit. Maybe I should put a 20 amp circuit breaker there.

I wish is was a 110v/240v motor. I'd just rewire it and connected it into one of my welding machine or compressor outlets. I don't do welding and woodworking at the same time.

Has a 110v only motor. At least I think so. 110v and 14 amps is just in the specs in the manual. The motor itself does not have a plate anywhere. Wait isn't that a UL requirement?


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## IC31 (Nov 16, 2012)

Just subscribing and hoping for some ideas to aid my JET 650 to do a better job - and already have found some.

As far as Harbor Freight - uhhhhhhh - I've found that they more then occasionally lie with specs on many products


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## Cherryville Chuck (Sep 28, 2010)

MAFoElffen said:


> Seems okay. Have some time now. Too hot to do much else. I'll pull the switch box and recheck the amp draw. Rated is 14 amp and looked at the older post where I checked it before the mod-- Is was pulling 6.2 amps.
> 
> Now pulling 8.4 amps on the same wire. (Rated at 14 amps.)
> 
> ...


I wouldn't think that there is very much different about our DCs from what you've described about yours but mine came wired 220v 9 amp. I never checked to see if I could change it since I was doing a lot of extra wiring in the shop at the time and I like my tools on dual voltage if possible. They seem to run better that way.


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## MAFoElffen (Jun 8, 2012)

I was off on specs a bit... assumed (14amps) which is others said on their HF 2HP's... My manual says:


> 120 Volts, 60 Hz, 2HP, Single Phase, 20 AMPS Peak


And I have it on a 20 circuit, but there are a deep freezer and a refrigerator on that circuit...

I plugged it into my jobsite power center... Explanation for others- 100 amp breaker box, populated with breakers, wired to 110v and 240v outlets... used to have electricians wire in temp power for construction crews)... I just have mine wired to a 240 amp plug so I can connect in. Anyways, it starts fine on it's own 20 amp circuit. So if I run a dedicated line/outlet for it, it will be okay.

Now seeing, if it still doesn't move enough air, the next step would be looking into reducing the back pressure. One to the major changes, is with moving more air, now the plastic and filter bag is really inflated hard... I guess we'll see.


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## MAFoElffen (Jun 8, 2012)

Question-
On dechyphering filtration... Which way does the scale go on microns? Is a filter rated 0.5 microns finer or coarser than one rate at 1.0?


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## Cherryville Chuck (Sep 28, 2010)

Finer. You're headed towards zero in size.


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## tvman44 (Jun 25, 2013)

My HF 2Hp DC draws 13 amps as it came from HF, no changes.



MAFoElffen said:


> Seems okay. Have some time now. Too hot to do much else. I'll pull the switch box and recheck the amp draw. Rated is 14 amp and looked at the older post where I checked it before the mod-- Is was pulling 6.2 amps.
> 
> Now pulling 8.4 amps on the same wire. (Rated at 14 amps.)
> 
> ...


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## Bradleytavares (Feb 25, 2012)

My HF DC only works on a dedicated 20 amp, 12 g. circuit. Anything more than a light duty drill, other, will trip the breaker when the DC starts up.


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## MAFoElffen (Jun 8, 2012)

Bradleytavares said:


> My HF DC only works on a dedicated 20 amp, 12 g. circuit. Anything more than a light duty drill, other, will trip the breaker when the DC starts up.


Thanks Bradley. It was doing it some before on that circuit. Now more But if the only it is the only thing on that circuit, it's fine.

Least I know it's just not me! Thanks again.


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## Tonto1 (Nov 10, 2016)

Thanks Chuck, that was a great read. It's nice to have people like Mike as members in the forum. Same with Home Theater!

I'm leaning towards using 6" pipe for the main run into the chip collector (concerned about the 1800 cfm into the chip collector). I don't really want to spend the $110 on a new impellar! I will only have 3 machines making dust (Table Saw, Miter Saw & Router Table). May use a reducing T & step down to 3" with another reduction to 2" at each machine. I can always open gates if needed. I haven't opened the HF DC yet, will do that tomorrow. I think Mike said somewhere it has a 5" intake. I'll see tomorrow...I'm sure I'll be improvising as I go. I'm liking the Thiel concept also. Again, this is all just thinking ahead if flow is a problem. Well see where we end up.


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