Multi-Purpose Box Fan

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Project by Carbide posted 03-26-2014 03:15 PM 3731 views 28 times favorited 25 comments Add to Favorites Watch

A friend of mine gave me an old squirrel cage fan out of his old furnace a couple of years back. I finally decided to put it to good use. I mounted the fan in a plywood box and incorporated a furnace filter. The furnace filter is washable so I will be able to re-use it reducing waste. When the fan is turned on it will now filter the dust out of the air. I have the top adjustable to allow for different table heights using it as an extension for my table saw or router table. I can also use it as a table for many uses including supporting my thickness planer while collecting dust when it is in use. Best of all it will be circulating filtered air throughout my work area while keeping me coooler.

-- When it feels like a job, it isn't a hobby anymore.

25 comments so far

View Gene Howe's profile

Gene Howe

12602 posts in 4885 days

#1 posted 03-26-2014 03:30 PM

Great idea! Much better than a ceiling mounted unit. So many other uses. One can always use another horizontal surface.
I now have a plan for the blower I’ve been saving for 5 years.
What part of IL are you in. We’re from the Effingham area, originally.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Gentile's profile


377 posts in 3275 days

#2 posted 03-26-2014 04:24 PM

I built one several years ago. It hung from the ceiling. I was amazed how well it worked. Cleaning the filter, showed me how much crud I was breathing. The shop had a lot less fine dust settling on flat surfaces. I like your idea of using it as a work surface.

-- "I cut it twice and it's still too short"

View Carbide's profile


210 posts in 3903 days

#3 posted 03-26-2014 04:59 PM

Thanks guys it is working out really well!

-- When it feels like a job, it isn't a hobby anymore.

View LesB's profile


3467 posts in 4900 days

#4 posted 03-26-2014 05:33 PM

I did the same thing about 15 years ago. I use a pair of standard size disposable furnace filters. The outside one is coarse and the inside one is a hepa type.
I use the top of mine as a sharpening center with my grinder and sharpening tools on it. It usually sits beside my wood stove so it can blow the heated air around the room while filtering the air. Also being movable I can take closer to the source of dust such as my lathe. While my portable vacuum dust collector gets most of the dust from the lathe there is always some that gets away and this blower gets most of that.

-- Les B, Oregon

View steve_in_ohio's profile


1195 posts in 3067 days

#5 posted 03-26-2014 05:34 PM

very cool idea, great job, I might have to make one of these

-- steve, simple and effective

View TDominy's profile


225 posts in 3999 days

#6 posted 03-26-2014 05:48 PM

Great multi use build.

-- By hammer in hand, all things do stand.

View Carbide's profile


210 posts in 3903 days

#7 posted 03-26-2014 06:59 PM

When I mounted the fan inside the box I have the fan with the rotation on the downhill side (Sort of like having your toilet paper dispensing over the roll which is the only correct way for your toilet paper to be mounted) to prevent the fan from blowing dust into my eyes. It ends up hitting me from about waist level down. I should take a poll. Who has their toilet paper mounted over the roll and who has it mounted under the roll???

-- When it feels like a job, it isn't a hobby anymore.

View woodchuckerNJ's profile


1607 posts in 3090 days

#8 posted 03-26-2014 07:36 PM

what kind of filter are you using? It looks like a plain spun fiberglass filter. You want to use a pleated filter with a high merv rating. Using a low value will actually do more harm to your lungs.

Merv 13,14, 15, or 16.

-- Jeff NJ

View jfk4032's profile


384 posts in 3983 days

#9 posted 03-26-2014 08:28 PM

Great idea to multitask…I’m in the middle of a build for a table saw outfeed table/downdraft table with a used furnace blower and motor. I’m also putting mine on wheels, but I like your idea of multiple tops. My main top will be drilled with a gazillion holes, but maybe I’ll consider other tops of differing thicknesses so maybe I won’t attach the downdraft top with too many fasteners now.

-- ---Joel; Central MD...rookie empter nester and getting back into woodworking!

View SCOTSMAN's profile


5849 posts in 5042 days

#10 posted 03-26-2014 09:11 PM

Wow it looks great well done. Alistair

-- excuse my typing as I have a form of parkinsons disease

View Cruiszr's profile


88 posts in 3049 days

#11 posted 03-27-2014 12:01 AM

It looks like you have a good design with your air system design. IMO everyone should make an effort to put some type of air filtration in there shop ASAP. Looks like you have plenty of space in your shop so I can see where mounting your AFS on wheels and move it around would be a benefit.
I don’t necessarily agree that the floor model is “much better” than the ceiling mount. I see lots of commercial ceiling unit on the market for workshop, but don’t remember seeing any floor model available. There must be some reason why the industry has chosen to mfg. units for ceiling mounts as oppose to floor models.
In my case, when I built my air filtration system I chose to mount it over my TS because it is the main tool in my shop and out of the way in my small shop. I needed to keep space open to be able to get around without bumping into something. JMO.

-- George R. Forest, Virginia

View vskgaming's profile


83 posts in 3071 days

#12 posted 03-27-2014 12:57 AM

thank you for posting this :), looks great

I just got a squirrel cage unit yesterday and planning to build something similar over the weekend. I too want something with casters instead of hanging it from the ceiling so i can use it for something else as well…


View dgage's profile


60 posts in 4427 days

#13 posted 03-27-2014 01:08 AM

Great idea. I really like the concept and execution and I could see it being very useful in my shop too. Thanks for posting.

View woodrangler's profile


3 posts in 3548 days

#14 posted 03-27-2014 01:09 AM

Your article is motivating. I saved off the fan and motor from our furnace when replaced. I’ll have to get after boxing it in with a filter. My initial thoughts were to just wire in a switch and plug it in.

Is the wall switch the only switch you used? Mine has multiple speeds. I haven’t been able to find a suitable speed control switch for the thing yet. Anyone have any ideas where to source one?

View tool248's profile


11 posts in 3295 days

#15 posted 03-27-2014 02:13 AM

Would a dryer’s squirrel cage fan work for this or is it too weak? I would imagine that a furnace’s fan would be much stronger since it has to push air throughout the entire house.

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