Homemade Cyclone Dust Collection System

Part 6: Ductwork

by Steve Silca

Money Savers

For the number of times Bill proclaimed that we must run 6” ductwork to all our machines, I decided to take his advice. It was not feasible for me to buy everything from Oneida – I would probably spend $2000. Here are a few things I did to save money:

My home-made blast gates. The collar has a 6 1/8" hole, and the gate has a five and 5 15/16" hole. Zoom in to see detail

1. I made 9 of my own 6” blast gates. The design is pretty straightforward. One thing that I did is make the hole in the collar that receives the ducting about 3/16” larger than the hole in the actual gate. This allows the 6” duct to insert into the collar and bottom out in the blast gate, and then it is easily sealed at the collar. To make these blast gates I drilled the holes in the gates (which are made of ¼” luan) with a large circle cutter on the drill press, set to about 5 15/16”. This was just right for the 6” duct to not go through the gate. These drilled fairly easily.
I wanted about a 6 1/8” hole in the collars, so the duct would slip through the collar and bottom out against the gate. As well, 6 1/8” was large enough for some of the ductwork fittings to fit into the gate as well. For instance, several times a wye inserted right into a blast gate and these fittings need about a 6 1/8” hole. The circle cutter was not cutting well through the ½” plywood that I used for the collars, so I made just one collar with a precise 6 1/8” hole. I then rough cut with a jig saw the holes for the rest of the collars to just under 6 1/8”, tacked each one over the perfect 6 1/8” template, and used a flush-trim bit in the router to make 17 more 6 1/8” collar pieces. These collars with their 6 1/8” holes were then glued to either side of the gate pieces perfectly centered over their 5 15/16” holes, leaving a 3/32” reveal all around. This is a little difficult to explain, so hopefully the above picture helps.

Planer, horizontal belt sander, and four-inch floor sweep hook-ups

2. I was lucky to have four metal blast gates and several plastic gates all in the 4” size from my previous system. As well, I had a few lengths of 4” spiral pipe and a great deal of 4” flex from the previous system. So, these costs are not included in the cost section of this site, since I didn’t have to purchase them. I was able to use these gates and lengths of pipe and hose only at the very end of duct runs, as the pictures show. For instance, the planer dust hood has a 4” outlet. So, the 6” duct was reduced to 5” flex, which was reduced to 4” right at the blast gate at the hood. Or, for the horizontal belt sander and band saw, I used a reducing wye and then installed the 4” blast gates and hose, since I think that these are large enough for the tools they serve. The only other place that 4” gates and pipe were used was for one of the floor sweeps, which has a 4” outlet.

3. I bought as much as possible from home centers (Menard’s and Home Depot around here) and as little as possible from dust collection supply companies. Home centers have the HVAC pipe, reducers, flexible elbows (I used a tremendous amount of these), hose clamps, and various take-offs, boots, and hoods that can be retrofit to work in the system. The only items I purchased from dust collector supply companies were the 6”x6”x6” wyes (at $20 a pop, I had 12), reducing wyes (I bought about six of these), a couple 5” and a few 3” blast gates (since I grew tired of making my own and they were only $10 and $6 respectively), and 3”, 5”, and 6” flex hose (since you can’t really find good flex hose for dust collection applications anywhere else, and Oneida is famous for their efficient flex hose). So, avoiding purchases from dust collection companies was difficult, as there are certain things you have to get from them, but I think I saved some money by going to home centers for the parts they had.

HVAC boot used as floor sweep

These money-saving ideas do not make the ductwork cheap by any stretch of the imagination, but they did save hundreds of dollars for me. For instance, for a few hours of work with scrap materials I had nine 6” blast gates that would have cost me $109 plus shipping. I saved about $200 by purchasing three HVAC boots, and making two cuts on them that turned them into phenomenal floor sweeps. As well, the adjustable elbows (of which I probably used 20-25), reducers, and ductwork are all just cheaper at the home centers.

A cost analysis of the entire system is located on page 8 of this article.

Special Considerations

Anyway, I took great pains to seal the ductwork UP TO every blast gate, because every leak that exists prior to a blast gate will be a leak that affects performance at every machine at all times. I was not quite as concerned with sealing every single seam after the blast gates, as these would not have a detrimental impact on overall system suction. The various sources of ductwork integrated well together – that is, crimped ends always fit into uncrimped ends.

Example of overlap technique
used to connect two uncrimped ends

I discovered a pretty easy way to handle two uncrimped ends meeting one another: rather than trying to create crimps or cut slits to make these things go together, I would just butt them against each other, and surround them with a short piece of snap lock duct ONE SIZE LARGER than the ducts that were being coupled.This piece merely wrapped around the joint (the snap lock was not utilized), overlapping itself, and was tightened down with two hose clamps. I used this technique about four times. The picture shows how the connection of an uncrimped end of an adjustable elbow to the uncrimped end of the miter saw hood is made by wrapping the two with overlapping 8” snap-lock (extra from the 8” diameter cyclone outlet pipe) and tightening with two hose clamps. It’s very cheap and it felt good to use the small pieces of ductwork scrap I had left over from cutting other ducts to length. Hopefully the picture and explanation help you understand this idea. I used 6” duct scrap to join two 5” uncrimped ends, 5” duct scrap to join two 4” uncrimped ends, and 4” duct to join two 3” uncrimped ends.

Sanding center

A few other innovative ideas I utilized were at the sanding center and the table saw. The sanding center, which is the bench that has the 1” belt sander as well as the 6”disc/4”belt sander, would necessitate two reducing wyes in addition to the wye off the main duct. This would be costly and take up more space than was there. So, I built a box with a 5” hole to the dust collector, a 4” hole for the 4” belt sander, and two 3” holes for the 1” belt sander and disc sander. I built custom dust ports for the belt/disc sander to capture the dust at the source, and the hood for the belt sander is adjustable so it can be put below the plane of the belt if necessary for longer parts sanding. The blast gates fit right into the box so they’re all centralized, and the box is secured to the wall.

Table saw vertical drop

The table saw vertical duct drop is removable. It is set back from the table saw about 15”, and allows ripping up to 43 ½” in its current location. I did NOT want it to run on the floor, and I didn’t want it to be further to the right of the table saw because it would interfere with walking through the shop. As well, since the surface planer is to the right of the table saw, it might get smacked a lot as boards are being run through the planer, brought back around to the front, and fed back in. I don’t anticipate disconnecting it often, since it allows me to rip 43 ½”. The only problem I foresee is if I’m using the fence as a stop block to cross-cut a long board or glue-up that is wider than about 15-18”. This is the only circumstance in which I see a board making contact with the duct, which will only happen rarely. So, I’m pretty happy with the layout.

Table saw dowel blast gate extension and lower HVAC hood hook-up

The other thing to note is that I extended the blast gate with a 5/8” dowel I had laying around, so I can open it from the front of the table saw. I connected the 6” duct to the table saw with an HVAC hood that takes it from 6” round to 10”x4” rectangular, which works out well for the base entry of the Unisaw.

The 6" main trunk goes diagonally across the shop

General Set-up

As the photos show, the set-up is essentially a 6” main trunk pipe running diagonally across the shop with several 6” branches coming off it. The longest duct run is to the miter saw, which is roughly 35 ft. of 6” ducting through a few wyes, and several adjustable elbows. I used no tees, only wyes. This cost more, but there is unanimity in the dust collection world that wyes are the right fittings to use. I located the blast gates as close to the collector as possible without putting them in an inconvenient location to use at each tool. I did this because the more duct there is before a blast gate, the greater the chance is that there will be a leak that affects the entire system.

Blast gates extend into ceiling when closed

Because of the design of my blast gates (they are the “self-cleaning” design), they can’t be installed against a wall to simply be pulled out when I want to use that machine. This is because when they’re closed, the moving part of the gate extends about 7-8” behind the gate. So, these gates were often installed along the ceiling above the machine, since there was just enough room in the floor joists above to shut the gates.

As much as possible, I used two adjustable elbows to make a 90 degree bend, as this would make a less abrupt, longer sweeping turn in the system. Oftentimes the 90 degree turn was coming off of a 45 degree wye, so only one adjustable elbow (set to 45 degrees) was required to complete the turn. These adjustable elbows were lifesavers for me – they allowed me to maneuver around all the crap that is found along our basement ceiling – heating ducts, plumbing and electrical pipes and fixtures, phone lines, etc. I couldn’t get a consensus on whether or not every seam on those adjustable elbows needed to be sealed or not, so, prior to the blast gates in the system I sealed every seam, and after the blast gates I only sealed the seams where the crimped end inserted into an uncrimped pipe. This sealing was all accomplished with duct tape, and the sealing at the blast gates (where the duct inserts into the collar of the blast gate) was done with duct sealant, and, in some cases, epoxy. Oneida’s site confirmed that the we don’t have to seal the long seam along the snap-lock pipe. All in all, I think that this recipe works well.

Tool Hook-up Specifics

6" flex to router table and 4" blast gate
to hook up to band saw with 4" flex

1. I ran flex hose to every machine that I foresee moving a little from time to time. This meant 4” flex to the horizontal belt sander (which is on wheels), and the band saw (which has yet to be hooked up but has that 4” black plastic gate designated for this tool), 5” flex to the drill press and planer, and 6” flex to the router table which may need to be adjusted from time to time depending on how it interacts with the miter saw, which is directly to its left. Also, the sanding center utilizes 3” and 4” flex even though those machines are stationary, merely because it was much easier to hook them up that way.

2. All other machines were hooked up with either a direct run of 6” rigid duct (radial arm saw, miter saw, two floor sweeps, jointer, and table saws), 6” reduced to 5” (one floor sweep), or 6” reduced to 5” reduced to 4” rigid duct (one floor sweep).

6" rigid duct right to cutterhead
3. At the jointer, the 6” duct is run right up to just below the cutterhead. Nothing escapes on this tool.

4. As indicated before, I used the 4” port on the planer, but ran a short length of 5” flex from a 6” wye, so that works just fine.

5" floor sweep using HVAC boot

5. Also as indicated before, I used HVAC boots and register adaptors in several places. My two 6” and one 5” floor sweep are adapted HVAC boots, I used a boot to attach to the table saw (which went from 6” round to 10”x4” rectangular). As well, HVAC fittings were used at the miter saw and radial arm saw, discussed next.

Radial-arm saw dust port

6. The radial arm saw collection is accomplished with a 6”x5”x3” wye. This wye has a 3” flex hose going to the front dust port of the blade then through a 3”x2” reducer. Behind the blade I used a common HVAC fitting that transfers the duct into a 10”x4” rectangle. I made a couple cuts in it to open it up and receive as much of the dust as possible, and on the left side I added an extender to do the same. I don’t ever really plan on using the various angle settings on the radial arm saw – it’s really only a rough cut saw that I recently inherited from a good friend of mine – so I went ahead and screwed the dust port to the table right up next to the blade at its 90 degree setting. Up to this point, I haven’t found it necessary to connect the 3” flex to a spring or bungee cord to hold it up.

6" miter saw dust port

7. The miter saw uses a similar HVAC fitting as the radial arm saw, but it is taller with a narrower opening, 14”x2”. I thought this was a better height for the way I wanted to collect dust from this tool. I pop riveted some wings and a small top to the HVAC fitting to capture as much of the dust as possible. It seems to do a good job. I considered using a wye like at the radial arm saw and running a hose to the port where the dust bag is generally attached, but seeing as all that dust gets shot directly backwards anyway, this would prove useless. All that comes out of the port gets sucked up instantly by the main hood. Cutting miters, this hood is not quite as good at collecting everything, but gets the job done. It certainly collects the fine dust from this tool which is what I’m most concerned with here.
I am considering getting a saddle-tee to tap into this duct run and have a hood to collect at the mortiser, which is right next to the miter saw.

Dust collection bag used to collect at the open-based contractor's saw

8. The 6”x6”x6” wye on the table saw drop splits to the Unisaw and to the contractor’s saw. These tools do not move much, so rigid duct was run right up to each of these machines. The 10” contractor’s saw presented a dust collection challenge, but I am pretty happy with my solution. It was accomplished by getting a dust collection bag from Harbor Freight (about $3.00) that fits open-based table saws. I cut a hole in the back of this bag, and fit a 6” starter collar through the hole. As well, I dropped a piece of ¾” particleboard in the bottom of the collection bag so it would keep its shape amidst the suction from the dust collector.

5" flex for drill press

9.The drill press currently has a 5” flex duct hanging down towards it. I bought 10 ft of 5” flex, and this is what was left after the planer run. This will be used in conjunction with various adaptors to collect from the drill press when it’s being used as a drum sander (I have a box with a collection hole), and also will just sort of rest on the table when doing large drilling operations hopefully collecting some of the fine dust that might result from those. This and the floor sweep next to it are where I used the two 5” blast gates I bought.

6x6x3 wye with adaptor for shop-vac hose

10. There is a 6”x6”x3” wye over the center workbench in the shop, along the run that goes to the miter saw. This has my third 3” blast gate which is hooked up to a 3”x2 ½” adaptor. I happened to have an extra length of 2 ½” hose for my shop vac, and this is hooked up to this gate. So, I can use this hose in conjunction with another adaptor (a 2 ½” x 1 ¼”) to collect dust from routers with dust ports and sanders. This set-up is great because the hose comes from above, and stays out of the way. This hose can also be used for general clean-up after hand planing or drilling on the bench.



11. There is a 5” branch duct that extends beyond the center bench over to the workbench with the pegboard. This is on the opposite side of the shop from the dust collector. I have no idea what it might be used for, but it’s there right above the bench if I ever need to tap into it.

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© 2003 by Steve Silca . All rights reserved.
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