Down Draft System

[Ron@Wood-Wonders.com]

My machine had to go back to CW for repair (3rd time in 6 mths) and UPS dropped and destroyed it. CW is sending me a replacement re-mfg machine tomorrow so that I don't have to wait till the claim is settled with UPS. While the service is great I'm not real comfortable with the re-mfg machine. I'm told the re-mfg machine will have all of the latest mods and upgrades and is actually better than a new one. We'll see....

While I'm waiting for the machine, I'm going to build a down draft system. Reading thru a few posts in the forum I think I have a pretty good plan but without the machine I'm not exactly sure how big to make the box. Can anyone tell me the measurement of the base and the slot in the bottom?

Also, if you've seen some good threads to look at let me know. I've been searching on "down draft" and dust collections" in the forum.

[gtj44]

I had the same thing happen to my machine. Had the board sensor quit and a few other things which were covered under warranty. Sent machine back before Thanksgiving and just got it back 12/28/07! LHR said it was repaired and sent back a few days after Thanksgiving, but the UPS driver dropped it somewhere between Texas and Buffalo. They claimed it was sent once, but never showed, called a few more times and it was sent out again and finnally received. Replies to phone calls were sporatic from LHR, they claim they are super busy!
One good thing, I was told the re-mfg machine comes with a new full year warranty plus got new bits, card and card reader. Wasn't required to send back the bits, card and reader with the old machine. Kinda makes up for the long wait.

[deemon328]

Your table needs to be a minimum of 24"x16". The slot at the bottom of the machine is around inch wide, but you need to consider other things first.

Firstly, what is the size of your dust collection system hose? In general, you'll have better performance and less stress on your collector if you size your opening to be roughly equivalent to your hose volume.

In my system, i have a 6" main going to the rectangular opening I cut. If I just cut a little slot, I'd place extra load on my collector. So, I tried to allow as much volume of air to flow as possible. I used a 4"x10" hole and did not weather strip the CW so that I'd get some air coming in from around the machine.

Also, the machine vibrates a lot, so I built in a little more size for stability. My table is 24"x24" with a 24"x36"top.

Anyhow, I just wanted to give you an extra option. Good luck with whatever you choose.

[DocWheeler]

Ron,

I just got my machine back last week, don't want to dismount it again.
If I remember right, the opening is about 2" X 17", I know that you want something exact, but I think that is what I made the duct opening.

To do the thing right you will need a blower rated at 600 to 800 CFM. My 475 CFM is a little too puny when the filter is coated with dust. I didn't have any Idea what I needed when I built it!

Talk with some heating/ventilating folks to see what you can get from them free (replacements and take-outs).

Maybe consider a seperate compartment with another filter to replace the "muffler", you would need some flex tubing, but maybe worth the hastle down the road. I've read where it was not a good idea to feed it into the duct of the table; for one thing, it would reduce your draw through your machine.

I found that you can get it all in a 24-26" square box (filter, blower, and catch-box). If I had it do over, I'd make a few changes and add more drawer space.

Of course, if you have a Dust Collection system already, you don't need any of these thoughts.

[HighTechOkie]

The bottom opening in my machine is 1 7/8" x 17" which equals 31.875 sq.in. The cross section of a 4" tube is 12.56 sq.in., 6" is 28.27 sq.in.

There are several factors to consider in a good dust collector (dc) system. How many tools(open ports) will be in use at the same time? How much static pressure the dc can overcome. Will you be in the shop while the CW is running? If so, then better filtration is important (down to 0.3 micron ideally, 1 micron filters are commonly used, while bags typically only filter down to 30 micron).

If you can provide info on what parts you have or are considering, number of tools in use at the same time, etc. we can get you fixed up with a well designed system to meet your needs.

Rob

[HighTechOkie]

Talk with some heating/ventilating folks to see what you can get from them free (replacements and take-outs).

HVAC blowers are a bad choice as they don't have the horsepower to move the volume of air needed with a good filter. Also, the motor is not sealed in those blowers so the fine dust powder will work its way inside and burn up the motor. Not a big deal for a freebie, but a hassle to swap and find a match in the future.

Rob

[John]

Your table needs to be a minimum of 24"x16". The slot at the bottom of the machine is around inch wide, but you need to consider other things first.

Firstly, what is the size of your dust collection system hose? In general, you'll have better performance and less stress on your collector if you size your opening to be roughly equivalent to your hose volume.

In my system, i have a 6" main going to the rectangular opening I cut. If I just cut a little slot, I'd place extra load on my collector. So, I tried to allow as much volume of air to flow as possible. I used a 4"x10" hole and did not weather strip the CW so that I'd get some air coming in from around the machine.

Also, the machine vibrates a lot, so I built in a little more size for stability. My table is 24"x24" with a 24"x36"top.

Anyhow, I just wanted to give you an extra option. Good luck with whatever you choose.

This is a common misconception. Dust collector motors are overloaded by too much air, not too little. You would do well to get an amp meter and check the load with all your gates closed vs. all of them open. BTW. It is just about impossible to overload a DC when you use any length of corrugated hose, unless you are using a much larger hose than the intake on the DC.

[deemon328]

Isn't that an unrealistic test though? The 6" intake port on the collector is a fixed size. Opening more gates doesn't magically allow it to take in more air than that. Of course doing that would cripple the performance of my single stage dust collector, but it's because of the drag that 100' of ductwork created, isn't it?

A more appropriate test is if you have one 6" duct open on the line to your CW location; don't limit it's ability to move air by undersizing an opening, then reduce it to a 2" diameter port and listen to the dust collector whine at you. I don't know how to measure like you suggested, but it's pretty clear that the dust collector hates me for limiting it's throughput. How is this wrong?

[DocWheeler]

HVAC blowers are a bad choice as they don't have the horsepower to move the volume of air needed with a good filter. Also, the motor is not sealed in those blowers so the fine dust powder will work its way inside and burn up the motor. Not a big deal for a freebie, but a hassle to swap and find a match in the future.


Rob,

Sorry to hear that the many of us that use squirrel-cage blowers on the exhaust side of the filter are doomed. It might not be the ideal solution for commercial equipment, but it is certainly adequate for this type on use.

[HighTechOkie]

Just doesn't make much sense to sacrifice my health to save a few hundred bucks as well as potential risk of fire. I merely point out the disadvantages. The final decision rests with each of us.

Rob

[Kenm810]

I’ve been very happy with my 3 speed squirrel-cage blower, 600 to 800 cfpm has plenty of air flow through the carver and the 1 and 3 micro filters. It’s been running fine for a year now and makes less noise than my $400 Jet shop air filter. If and when the time comes to swap the blower out, I only have to remove 4 screws and wires about 10 minutes time, plus I already have a free matching used backup blower from a local Heating and Cooling company that normally just discards them. As far a health concerns, I get hundreds of times more fine dust leaking through the bags on the commercial two stage shop system on one table saw in hour or two than I get from my self contained DD cabinet running 6 to 8 hours. If you look, half the sanders, drill presses, band saw, lathes, and other electric motors use in the shop have no dust or fire protection. ---- Just My Opinion

[HighTechOkie]

Glad you joined in Ken. I meant to inquire about your setup. Can you look on the blower motor for its HP rating? What filters are you using? How ofter do you replace/clean those filters? Could you take a photo of the motor showing how much dust has collected on it?

Regarding the other shop tools w/o dust/fire protection, those motors are not sitting IN a continuous dust stream either. We also know that fine sawdust powder can be highly flammable under the right conditions. Its a foreseeable and preventable situation. Is this possible with collecting dust just from the CW? I don't know.

I just want to make sure people understand what they are getting into, and should they choose to continue down that path, they at least have a better idea of things to consider.

If the only purpose of the dc is to pull the chips away from the CW, then a diy hvac blower down draft is probably ok.

Rob

[Ron@Wood-Wonders.com]

The bottom opening in my machine is 1 7/8" x 17" which equals 31.875 sq.in. The cross section of a 4" tube is 12.56 sq.in., 6" is 28.27 sq.in.

There are several factors to consider in a good dust collector (dc) system. How many tools(open ports) will be in use at the same time? How much static pressure the dc can overcome. Will you be in the shop while the CW is running? If so, then better filtration is important (down to 0.3 micron ideally, 1 micron filters are commonly used, while bags typically only filter down to 30 micron).

If you can provide info on what parts you have or are considering, number of tools in use at the same time, etc. we can get you fixed up with a well designed system to meet your needs.

Rob


I'll being using a DC with a 4" hose to connect with the down draft. The DC is on the small size so it will be dedicated while running the CW.

My shop is real tight for space and don't have room for a dedicated stand so I plan on making a box 24 x 26 and 6" tall box attached to the base of the CW using the base mounting holes. I'm going to build a 3 sided box in the middle under the slot and then tap in PVC pipe routed to the front and rear to address the needs I see in the forum.

[Kenm810]

The blower in the cabinet right now is a ½ hp 115volt 1075 rpm 3 speed Dayton, the spare blower is a ½ hp Patton Electronics 1075 rpm 3 speed same size. Both, I was told were less then 12 years old, the one in my last house was 25 years old and still running strong when we sold the house and built our new home. The filters are 3m Filterete Pleated Dust and Pollen 600, 1000 filters and equivalent. The filters and dust chambers are cleaned at the end of carving every day, or after each carving done in Corian or SignFoam because of the ultra fine dust.
These photos are from today ( no cleaning or touch ups ) You can see some dust on the squirrel cage, also on the floor of the blower chamber near the lower door hinge.
The motors are thermal and over load protected ( UL requirement ). The Cabinet, Blower, and machine are all grounded, plus I’ve Had no static electric problems at all. I’m not trying to say that this is the way to go, to anyone. --- It’s just my way.

[TIMCOSBY]

does it have a lot of suction? i picked up 8 of those fans from a local a/c company ... they just throw them away. mine are all 220volt. they said they get 110v every now and then. just wondering befor i hook one up how they suck.

[Kenm810]

They have Plenty of Suction, mine has a 10" round by 12" long squirrel cage that can nearly slam the dust conpartment door
off its hinges, if someone was foolish enough the open it while the blower is running on high speed ( I was http://www.carvewright.com/forum/images/smilies/icon_rolleyes.gif).
But most of the time I keep the DD Cabinet on its medium speed.

You have to remember these blowers were used to move all of the air in a heating and cooling system for an entire House. Plus I've noted that even after some 51/2 hour carving projects, mine has never over heated or acted as if it was being starved for air. They have performed very well as the major component in the dust control system of my DD Cabinet.

Ps your design or application may and possibly will be far superior to the DD Cabinet I use.
I just did it my way

Only an observation

[Gunner]

Ken,
Very nice setup. That would help in my shop because of limited space.Thanks for the pic's.

Gunner

[pkunk]

I use my 3 hp cyclone on my CW, but I built a DD sanding table years ago with a 2300CFM squirel cage that really sucks. It'll run some days for hours and never get warm.

[Kenm810]

pkunk,

Great photos, 3 hp - mmm - That's what we need ( More Power ),
"Warning -- Warning" Don't ever go to near or lean over that DD Table with 'A' Long Hair or with 'B' a Neck Tie on,
ya might find your in the dust box lookin out.
Of course I'm sure that You or I wouldn't have to worry much about counts either A or B.
The 60s or 70s since I had long hair and I can't ever remember walking around my shop with a tie on. http://www.carvewright.com/forum/images/smilies/icon_razz.gif

[pkunk]

Heheh, funny you should mention things getting caught. I was cleaning my PC dust bag in front of a 5" DC opening when the suction grabbed it (and my hand) so fiercely I let go. I had to fish it out of the DC 55gal barrel 50 ft away. I thought I was going through too.:p

[TIMCOSBY]

Ken,
Very nice setup. That would help in my shop because of limited space.Thanks for the pic's.

Gunner


building the box for the fan on the outside wall of the shop and running pipe and blast gates on the inside because my space is tight too.

[John]

Isn't that an unrealistic test though? The 6" intake port on the collector is a fixed size. Opening more gates doesn't magically allow it to take in more air than that. Of course doing that would cripple the performance of my single stage dust collector, but it's because of the drag that 100' of ductwork created, isn't it?

A more appropriate test is if you have one 6" duct open on the line to your CW location; don't limit it's ability to move air by undersizing an opening, then reduce it to a 2" diameter port and listen to the dust collector whine at you. I don't know how to measure like you suggested, but it's pretty clear that the dust collector hates me for limiting it's throughput. How is this wrong?

It is wrong because the "whine" you hear is the DC picking up speed because it is not under load. The same thing happens with a vacuum cleaner.

[Kenxxx]

I have a built-in Oneida dust collection system that is rated up to 1350 cfm and have two quick disconnect flex hoses availabe in my shop. I built a wooden box 6" high x 18" deep x 26.5" wide to exactly fit the recessed top of a four drawer roll around tool cabinet (mine is a Craftsmen, but other brands appear to be the same size). I tilted the CW up on the end opposite the display and accurately measured the slot size and location, as well as the mounting hole pattern, plus I removed the four rubber button feet on the bottom ( I saved them for reinstallation in case I have to send the machine in for repair). I cut the slot opening in the top of the wooden box and drilled four mounting holes to match the machine base. I installed 1/4-20 T-nuts on the underside of the box top so I could install mounting screws from the top of the machine base. I bought a 3/8" soft rubber anti-fatigue pad (by the foot) at Lowes and used a Sharpie to trace the outline of the CW base on it, including the four mounting holes. I used an Xacto knife to easily cut the gasket to shape. The gasket not only seals the suction path, but seems to dampen vibration/noise. The inside of the box has a sloped hopper leading to a 4" quick disconnect plastic adapter on the right side which connects to my built-in dust collector system. On the bottom of the box, I installed 3/8" closed cell, adhesive backed weatherstripping to dampen the box on the top of the tool cabinet. The dust collection is very effective, probably 90%. I also changed out the original casters for all swivel with soft rubber tires and dual axis ball bearings. This also contributes to dampening the vibration/noise, plus I can easily roll the carver out for use and I have four drawers to hold all my tools, cutters, etc.

[Kenm810]

Hi Ken,

Your set up sound like a great dust and chip control system,
I especially like your use of the 3/8" soft rubber anti-fatigue pad as a sound and vibration limiter.
I’ve been putting it off for a while, but since you mention being able to buy it (by the foot) at Lowes,
that’s where I’ll be this coming Saturday to pick some up.

Thanks for reminding me

[fwharris]

I have a question on my thoughts for my DD project. I bought a computer printer stand top. Got this at the local Habitat for Humanity recycling center for $3. I have found this a good source for some cheap supplies. It already has the rectangular opening that is very close to the opening on the bottom of the CW machine. My short term plan is to build a box for this to sit on and use my shop vac. Note that is my short term plan until I can $$$ for a DC system. I already have put enough $$$ into my "hobby" so am trying to get by for now.

To the Question...As long as I do not use plastic for my "duct work" from the vac conection of the box to the cut out bottom of the top is there a concern for static build up? I plan on using metal vent pipe as my duct work inside the box.

Any other tips/tricks on this would be welcome!!!

Ken, I really like your design for your system. The pictures you posted really got me thinking about what I might do for my actual system. I do have a possible source for the blower unit and will be checking that out..

[Kenm810]

Hi FWHarris,

Static Electricity can be a real machine killer, it can stop a project cold,
or toast your Circuit boards and even mess up you sensors.
Just to be on the safe side run a ground wire to your machine and duct work.
There are several posts and threads about static potential,
and I think it would be a good idea to read up a little
to see how other folks have dealt with their Static Problems.

[Sarge]

pkunk,
Great photos, 3 hp - mmm - That's what we need ( More Power ),
"Warning -- Warning" Don't ever go to near or lean over that DD Table with 'A' Long Hair or with 'B' a Neck Tie on,
ya might find your in the dust box lookin out.
Of course I'm sure that You or I wouldn't have to worry much about counts either A or B.
The 60s or 70s since I had long hair and I can't ever remember walking around my shop with a tie on. http://www.carvewright.com/forum/images/smilies/icon_razz.gif

pkunk Heheh, funny you should mention things getting caught. I was cleaning my PC dust bag in front of a 5" DC opening when the suction grabbed it (and my hand) so fiercely I let go. I had to fish it out of the DC 55gal barrel 50 ft away. I thought I was going through too.


Sounds like somebody has been watching "Tool Time" with Tim The Tool Man Taylor. :D :D :D

Paul, did you by chance act as technical advisor??? The Benford 5000 DC, perhaps?

[fwharris]

Hi FWHarris,

Static Electricity can be a real machine killer, it can stop a project cool,
or toast your Circuit boards and even mess up you sensors.
Just to be on the safe side run a ground wire to your machine and duct work.
There are several posts and threads about static potential,
and I think it would be a good idea to read up a little
to see how other folks have dealt with their Static Problems.

Ken,

I got the box built and did a test cut (calib. offset) on a 3" bd and it really sucked the chips and dust down. Of course this is not very much since it is short carve but it did work.
I ended up doing it all in "wood" ( easier to work with and I have it). the Frame is 2 x6, box for duct under the top is 4" x 20", the top is from a HP printer desk. it is sitting on a roll arountd tool chest. Did need to down size the opening in the top.

I did do about 2Hrs of reading the forums tonight on down drafts, dust collectors, static plus all of the side discussions in each that really had nothing to do with the actual post :p;):rolleyes:.
Lots of good info, learned a lot plus got to find out about most of the guys who basicly started this CC/CW..
Also like the comments about the use of static control spray using fabric softner, use of tool chest for base.

About the static, I will need to run a ground from my grounding rod that is on the outside of the garage to a close locating so I can clip it to the grnd wire that I will run from the frame of the CW.

[Jeff_Birt]

About the static, I will need to run a ground from my grounding rod that is on the outside of the garage to a close locating so I can clip it to the grnd wire that I will run from the frame of the CW.

Is this grounding rod connected to your electrical system? It should be. Grounding rods just 30'40' feet apart can have 50 or 60 volts difference in potential between them. It is a huge shock hazard.

[fwharris]

Jeff, yes this is the grnd rod that is tied to my elec panel at the garage.
It wil be about 20' from where I plan to use it at the shop vac. I plan on connecting to the rod itself not in the elec box.
Or would I be better off doing a seperate grd rod just for this purpose?

[Jeff_Birt]

Or would I be better off doing a seperate grd rod just for this purpose?

No, that is my point. You do not want a separate ground rod (by separate I mean not electrically connected to your electrical systems ground rod). Many times there will be more than one ground rod or source or ground, like a ground rod by the meter base, water pipes, etc, but all these should be connected together.

If your ground rod is the ground for your electrical system than your fine.

[fwharris]

Jeff,
You are Jeff on the spot this morning!! I was sure I needed to be on a good elec. grnd just had to ask for better clarification. Thanks...

Since you are here on question on the LCD display. when I go into a carving function, like calb offset that I did to check my DD, It goes blank. I try adjusting the contrast and all I get is Blank to all squares. Is this an issue?

[mchristle]

I have been looking into adding dust collection recently. I have noticed that everyone seems to use a system that vents down through the hole in the bottom of the CM machine. This does not make sense to me. All the dust collects on the top of the board, where it is being carved. I looked all over inside my CW and I just don't see how the dust gets around the board to the port in the bottom. What am I missing???

[twehr]

I have been looking into adding dust collection recently. I have noticed that everyone seems to use a system that vents down through the hole in the bottom of the CM machine. This does not make sense to me. All the dust collects on the top of the board, where it is being carved. I looked all over inside my CW and I just don't see how the dust gets around the board to the port in the bottom. What am I missing???

Wide boards collect more because they cover so much of the opening. Narrow boards allow more access, so they result in more collection.

I use a 14" sled most of the time, so downdraft does little for me. Top-end collection should help.

Look at this post (http://www.carvewright.com/forum/showthread.php?t=6070) (post #16) by DigitalWorkshop.

[TIMCOSBY]

I have been looking into adding dust collection recently. I have noticed that everyone seems to use a system that vents down through the hole in the bottom of the CM machine. This does not make sense to me. All the dust collects on the top of the board, where it is being carved. I looked all over inside my CW and I just don't see how the dust gets around the board to the port in the bottom. What am I missing???

doing a collector that attaches to the lip in front of the cutter head that is maybe 1/4" above the board and has a 1/8" slot the length of the machine. just waiting on warranty to run out so i can dill some holes.

[pkunk]

Essentially, the wider the board the worse the dust collection will be from a downdraft system. With my DC at 1800 CFM i'm still left with dust on top of a maximum width carving, but a small blast of low pressure air periodically keeps it clean enough. A shop Vac is not the best way to clean while carving (search static), but a little help from an air compressor works. Absolute cleanliness while carving is not necessary. I've run 6-10 hour carves many times with the machine moved to an empty garage so I could think in the shop, without benefit of even the downdraft DC, with no ill results. When I can afford to not be in the shop, running the DC for the CW is the best way to go, but not mandatory.

[gtj44]

I saw this in the Dec/Jan issue of Wood Magazine. A mini dust collector.
This may be the answer for the hobby users of the Carve Wright with tight space. Looks like it be swapped around on multiple machines. Just thought I'd share the info. If the link doesn't work directly from here, go to the main web site www.steelcitytoolworks.com

then search for dust collectors.

www.steelcitytoolworks.com/products_tools.cfm?section=2&category=5&tool=65115

[fyrpuppy]

I am not sure about the 4" port reducing down to the exhaust port. We tried to connect a DC system to the 2" piping in the sign shop at work and it decreased the volume so much it wasn't worth it, a wet/dry vac worked better. This system was not hooked up to a carvewright just some bench tools and and a couple of engraving machines.

[Kenm810]

I think it would be intended as a dust and chip collecting attachment to the modified front
of the CW or CC machine, similar to the way Al from Digitalwoodshop has modified his machine.
To maximize the use of its full 4" intake, and not limiting it to the small exhaust port on the back of the machine.