DD air supply

[klingler]

I'm getting closer to getting my DD table built. I can tell you it's not nearly as spiffy as some of the tables you craftsmen have built, but I believe it will work well.

I picked up a squirrel cage from work. It was just used to blow air on the employees who work near the hot ovens in the factory so it has a rounded piece of aluminum duct that extends about 12" and is about 4" in diameter at the exhaust end. Since I don't have a large air compressor to blow onto the top of the work piece, I want to try and capture some of the air from the the blower and feed it in through the top along the flex shaft. I realize this will be difficult since it is not compressed air, but I hope to get some. I know it won't take much get the dust air-born, and that is really all I need. Any ideas how to do that? Please astound me with your brilliance. You haven't let me down so far!

--
John

[twiceretired]

There was a post a while back where the person used the exhaust from the CW as an air supply to blow the chips away from the carving bit. Simple and intuitive.

[Digitalwoodshop]

Use a foam seal to close off the center slot on the bottom of the machine. You don't want to suck air through the vents on the bottom of the machine as it will suck dust through the power supply and computer area.

Don't think the blowing air back into the unit is good, you will make airborne a lot of fine dust.... Not good to breath... Be sure to have a filter on the output of the DD.

AL

[Steven Alford]

There was a post a while back where the person used the exhaust from the CW as an air supply to blow the chips away from the carving bit. Simple and intuitive.

I have mine hooked up to the exhaust of the CW and I don't get enough air pressure. I have even tried the aquarium air pump idea and that does not work either. What do other people use for the air to the tube some of us have added to blows chips away from the bit?

[fwharris]

I have mine hooked up to the exhaust of the CW and I don't get enough air pressure. I have even tried the aquarium air pump idea and that does not work either. What do other people use for the air to the tube some of us have added to blows chips away from the bit?

I use the aquarium pump (4 outlets) and found the same thing you did Steve, to low air pressure. What I did was use a 1/4" tube connector for drip tubing and melted down the end to close up the hole a bit. That made for higher pressure to blow the dust away from the board..

[Steven Alford]

The end of my tube is metal, so I smashed the end a little but it still does not have any pressure.

[atauer]

check for leaks in your hose. Even a small leak can cause pressurization problems.

[PCW]

I use one of these commercial aquarium pumps and have more than enough air. Around $55 to $60

Eco Plus 1 Specifications:

- 18 watts
- Single Outlet
- 38 Liter/min (1.34 CFM)


http://www.aquacave.com/images/AE-SS-EP1.jpg

[klingler]

Good information guys, I really appreciate it. But I want to try and just use the squirrel cage to produce the forced air into the tube. I know it would be hard to produce much of an air flow into such a small opening, but I have to think there would be some way.

[fwharris]

Good information guys, I really appreciate it. But I want to try and just use the squirrel cage to produce the forced air into the tube. I know it would be hard to produce much of an air flow into such a small opening, but I have to think there would be some way.

Klingler,

do a search on Kenm810. I think he has several pictures under the "dust collection" thread. He uses the air from his squirrel cage dust collection system for his air push...I think!!!

[fwharris]

The end of my tube is metal, so I smashed the end a little but it still does not have any pressure.

How big of a air pump are you running and how many outlets does it have?

Mine is 4 outlets..

also SteveEJ has an air pump set up (that is who I got the idea from) did some step down type of stuff to get better pressure..

[Kenm810]

I’ve been watching this thread, and the different ways everyone has added forced air to their machines.
In the Last 2 ½ to 3 years I’ve tried them all ---- I finally settled on dry compressed air,
to get the 7 to 12 Lbs. of air to move the dust and chips out of the carving,
off the top of the project board and out of the machine through My DD Cabinet with out blowing them under the rollers and into the electronics.
The compressed air in my shop at work is supplied by a 70gal compressor and 2 80Gal makeup tanks that supply the entire building
--- at home my little 12gal compressor does just as good of a job.
I run a 3 speed twin squirrel cage Negative Pressure DD system -- 600, 800, 1200 cfms as needed.
All three vents or Ports run directly in to the top chamber, then down through the filter compartment,
Then once the is dust and chip free out of third blower compartment and the cabinet.

It works for Me :cool:

[fwharris]

I’ve been watching this thread, and the different ways everyone has added forced air to their machines.
In the Last 2 ½ to 3 years I’ve tried them all ---- I finally settled on dry compressed air,
to get the 7 to 12 Lbs. of air to move the dust and chips out of the carving,
off the top of the project board and out of the machine through My DD Cabinet with out blowing them under the rollers and into the electronics.

It works for Me :cool:

Ken,

Well I was only partially right or wrong????

Thanks for re posting your pictures!!!

[Frederick_P]

I have spent a lot of time building my downdraft table and even duplicated the little blower that Ken showed us and I would have to agree with Kenrik that this system does not seem to work with wider boards simply because the board blocks the airflow to the point where the dust is not efficiently removed. Also I found that with the blower, the profile of the carve cane actually result in the dust being directed into wrong locations and accumulating where I least want it.

I feel that the real answer will have to be a dust collection system that sucks up the dust at the source. I am thinking of a long plenum with a narrow slit that will sit on the shelf of the machine so that the slit is a couple of centimeters from the carving bit. Haven't worked out the details yet but when I get the drawings made I will post them for feedback.

[Steven Alford]

I have spent a lot of time building my downdraft table and even duplicated the little blower that Ken showed us and I would have to agree with Kenrik that this system does not seem to work with wider boards simply because the board blocks the airflow to the point where the dust is not efficiently removed. Also I found that with the blower, the profile of the carve cane actually result in the dust being directed into wrong locations and accumulating where I least want it.

I feel that the real answer will have to be a dust collection system that sucks up the dust at the source. I am thinking of a long plenum with a narrow slit that will sit on the shelf of the machine so that the slit is a couple of centimeters from the carving bit. Haven't worked out the details yet but when I get the drawings made I will post them for feedback.

Check out Floyd's site.....

Ringneckblues.com (http://www.Ringneckblues.com)

He has already got one made for us and it works quite well.

[Frederick_P]

Steven, this looks like it would work, although I am not too keen on cutting up my machine door. I am thinking of something a little less bulky but so far this one looks like the best alternative. Unless I can come up with anything better, I'll probably buy it!

[Steven Alford]

You only need to cut off the bottom one inch of the cover. And that was very easy to do. I just clamped a metal straight edge at the 1" mark and cut it with a hacksaw, file it a little and it was done. No harm to the machine at all.

[Steven Alford]

I’ve been watching this thread, and the different ways everyone has added forced air to their machines.
In the Last 2 ½ to 3 years I’ve tried them all ---- I finally settled on dry compressed air,
to get the 7 to 12 Lbs. of air to move the dust and chips out of the carving,
off the top of the project board and out of the machine through My DD Cabinet with out blowing them under the rollers and into the electronics.
The compressed air in my shop at work is supplied by a 70gal compressor and 2 80Gal makeup tanks that supply the entire building
--- at home my little 12gal compressor does just as good of a job.
I run a 3 speed twin squirrel cage Negative Pressure DD system -- 600, 800, 1200 cfms as needed.
All three vents or Ports run directly in to the top chamber, then down through the filter compartment,
Then once the is dust and chip free out of third blower compartment and the cabinet.

It works for Me :cool:


Hey Ken,
In your second picture, where did you get the valve setup for the air compressor?

I like that idea. My compressor is running the whole time I am carving (use it to blow out the machine when it is done carving) so why not use the air.

[fwharris]

Check out Floyd's site.....

Ringneckblues.com (http://www.Ringneckblues.com)

He has already got one made for us and it works quite well.
You only need to cut off the bottom one inch of the cover. And that was very easy to do. I just clamped a metal straight edge at the 1" mark and cut it with a hacksaw, file it a little and it was done. No harm to the machine at all.



Steve,

Thanks for the plug!!! :)

I used a dremil tool with a cut off wheel to trim mine down. I believe it was Hess that said he just scored it with a utility knife several times and snapped it off.

[al2888dj]

works great, used with 1-1/2 hp fox dc system very little dust

[fwharris]

works great, used with 1-1/2 hp fox dc system very little dust

Alex,

Thanks!!!! Sure glad it is doing it's job for you!!