Dust collector woo's

[Art]

I've got a 2hp dust collector with lines throughout the shop to each piece of machinery. Because emptying the bag was such a pain, I installed a 30 gal garbage can separator in-line just ahead of the collector itself. Everything is light duty 4" pvc pipe to the blast gates, then 3 or 4" hose to the equipment itself. My problem is that the dust, chips and shavings seem to pass through the separator into the lower bag of the collector. Once the bag gets full, it then fill the separator can. Logic tells me I might have too much suction which I never anticipated as a problem. So first, is my guess correct and if so, is there a solution?

Any help is appreciated, Art Learmonth

[Morris Dovey]

I doubt the problem is too much suction. It /is/ necessary to keep the container under the cyclone lid less than 25% (give or take) full.

I have a similar set up (for a single machine) that works really well. Photos at

[Eddie Munster]

Sounds like my setup. 2 hp, 4 inch pvc. Same thing happened. The dust collector kept the can nice and clean. Hah! I imagine if you have to use one, perhaps a deeper can experiment is in order? I just put up with the bag but am thinking about attaching a lower bag to a can, somehow.

John

Art wrote:

[Folklore]

3" and 4" is really small. More than likely you have too little airflow and you're not creating a cyclone in the seperator which is necessary for the chips to fall out. You likely need something along the lines of 6" mains and 5" drops to your tools. Be careful to design for as absolutely small a static pressure as possible since big-bag type systems have a very steep fan curve. Also, make sure everything is extremely well sealed, especially the seperator. Also, the seperator will collect chips, not dust. Dust will still go into your DC.

[Bob Davis]

webpage and I have no idea what your talking about. You don't define them anywhere and I sure can't figure it out from the pictures. Could you please provide some clarity about these terms:

Shop Bot dust collector shoe z-carriage shoe box

Bob

[Bob Davis]

I suspect all separator lids are not created equal. I believe the ones like Rockler sells at

are the poorest design. The Lee Valley lid at is better. I built my own with PVC pipe fittings. Its similar in design to what woodcraft sells at

[Morris Dovey]

Sorry about that. The web page was built for other ShopBot users

- and nearly everything you asked about is at the top of the page.

This is the machine that the dust collector collects from - the blue monster with the MDF tabletop. It's capable of producing /huge/ amounts of dust & chips.

A box that surrounds the router bit and to which the DC hose is connected.

The 'Bot can move the router bit in three dimensions: x and y lie in the table, and z is up and down. The spindle rides up and down on a movable frame called the z-carriage.

The dust collector "shoe" without hardware, DC flange, etc - a box with only 5 sides.

Bob, since posting my original response, I've been wondering if your 30 gal. can might not be a bit small for the job. I haven't experimented with different container sizes - but with my 55 gal drums, very little gets past the first drum...

[Morris Dovey]

Bob...

More apologies. I confused you with Art (the OP). You can see a bit more of the machine at

[Chris]

Try attaching a 6 to 12 inch piece of pipe to the center hole inside the barrel (the one attached to you dust collector) you will have to change the barrel more often but it should give the heavier pieces more time to settle out before going to your dust collector. To many of the vortex creators have the intake to close to the exhaust not giving the air flow a chance to swirl and thus you do not get any separation of materials.

CHRIS

[Art]

Morris,

Thanks for the info. What exactly does a Shop Bot do?

BTW - I'm in Newton, but I don't even know where DeSoto is.

Art

Morris Dovey wrote:

[Morris Dovey]

It's a PC-controlled robot. Mine is outfitted with a 5HP spindle whose speed can be controlled in 0.1 RPM increments over the range of 0 - 24000 RPM - and I use it (primarily) for routing. Some people install plasma cutters, laser cutters, grinders, saws, etc. It's a (relatively) inexpensive flexible platform with a reasonable degree of accuracy for woodworking, some mold making, and some metalworking (milling/drilling) applications.

One of the features I like is the ability to process DXF files (from CAD programs) automatically to finished parts.

You can see some of what it can do at the ShopBot web site:

is a very small town located at exit 110 on I-80 - about

54 mi west of Newton (home of Maytag, the well-known appliance manufacturer).

[Edwin Pawlowski]

Nothing to add, just wanted to fix the subject line. :)

[Bob Davis]

Thanks for giving answers to all my questions, Morris. I learn something new every day reading here.

Bob

[Tom Veatch]

-snip-

-snip-

I suppose those are pretty good (relatively) prices when you are talking about CNC machinery, but they do make the cost of my cabinet saw seem almost like pocket change. However, if the Dow hits 20000, and my index funds follow ...

Tom Veatch Wichita, KS USA

[Morris Dovey]

Like your cabinet saw, they only make sense when they satisfy a requirement that can't reasonably be met using a lower cost alternative. In my case, I wanted to produce a structurally complicated product of consistantly high quality. Production with "traditional" tooling would be prohibitively expensive; and so the CNC solution was the only path available. The ShopBot PRT-96, while at the lower end of the CNC cost spectrum, provides all of the features I needed.

Because it does its job so rapidly, I have both personal and machine time available for experimentation and learning - I'm discovering that there are joinery techniques possible with CNC that just wouldn't be reasonable to consider using traditional methods; and that we've just begun to scratch the surface of what's possible.

I spent part of my time this past week working on a low-cost linear bearing design based on an extruded frame to contribute to an "open source" kind of CNC development. That project aims to make a basic 3-axis CNC capability available in "some assembly required" form for less than US$100. If that effort is successful, you won't need to wait for the Dow to hit 20000...

[B a r r y]

Check the angles of the lid's entrance and exit fittings. You need to create a circular, cyclonic flow. If the flow isn't circulating, the chips can't fall, they get sucked right into the other hose.

Dust will go all the way, chips and shavings should fall into the trash can.

Barry

[Art]

Thanks for doing that. I knew it didn't look right, but forgot to use the spellcheck.

Art

Edw> Nothing to add, just wanted to fix the subject line. :)

[Wally Goffeney]

Art,

The advice that a couple responders gave you about properly designing for cyclonic flow was right on. I made my separator lid (for a 30 gallon galvanized can) using a 4" 90degree elbow and a separate length of 4" straight pipe. It's geometry is very similar to the Woodcraft separator that was posted, except the straight pipe extends about 6" below the elbow inlet. This allows for development of cyclonic flow, as another of your respondents suggested.

I empty the separator can when it is half to two-thirds full. Probably empty it 30 or more times before I have to empty the bag.

Wally Goffeney