Dust Skirt and bit life

[ribbons@newformresearch.com]

We cut 1/2" hardboard (Masonite) with a 3/16" bit and dust collection is a real problem with the standard dustskirt which places the suction 5 or 6 inches from the bit. There is also a large perimeter of brush bristles where the vacuum is lost before it gets to the bit or into the cut.

Recently we developed a dustskirt which places the vacuum right around the bit/collet. This is vastly better for dust pickup and I have noticed bit life to be dramatically extended. I haven't kept records but I am sure the bit life is up over 50%. This is probably due to taking the dust out a very narrow cut slot so the friction on the bit is reduced as well as cooling the bit in the much stronger airflow.

I would advise anyone who is interested to look at upgrading their dust collection system to pay close attention to the workings of the dustskirt. A much smaller dust skirt focused around the bit can really pay off.

Has anyone done any work on dust removal/bit life?

Regards,
John M.

[joe]

Great Post John,

We have been cutting Extira which causes lots of dust also. But haven't found a way to improve the collection device.

Could you post a photo of your's.

J

[ribbons@newformresearch.com]

OK, here are a couple of pictures. I've used a Tupperware container glued to the bottom of a base plate along with a rubber toilet plunger and paper plate - 4 parts plus the 3" pipe.

The Tupperware container contains the vacuum. The paper plate prevents the PC router from blowing down into the container and spoiling the vacuum and the rubber plunger acts as a brush to further focus the vacuum.

Note, I used Lepage 9000 adhesive to stick the plunger head and the base plate - (1/4" plywood)to the Tupperware. I don't know of anything else which will work on polyethelene to rubber.

The plunger head is sliced every 3/8" so it doesn't catch on anything.

Make sure the gap from paper plate (or whatever) to the bottom of the Tupperware container is at least 1" to allow the full vacuum airflow.

I'll try posting the photos. Get back to me if they don't work on the board and I'll send them direct.

Regards,
John M.

[paco]

I'd be curious to see John... thanks in advance!

[mrdovey]

I put together a simple box "shoe" that's worked really well for me (for everything I've cut.) There are photos at: http://www.iedu.com/DeSoto/dust_collection.html

[ckurak]

Morris,

How noisy is that dust collector?

[stickman]

I'm interested in seeing a few of these "tupperware" pictures. I am still working on a better dust collection system, at the tool head. My last one was a little too small, and it got ATE by the router. I also need to work on the adjustablity, I need something quicker than my pipe clamps and nut driver.

Jay

[gerald_d]

I'd be curious to see how well a Lee Valley style "cyclone lid" works on a more square bin like this one:


4988

I have 300 of these bins (about 60 gal. (240 liter)) in my shop at the moment - but that is another story....

[stickman]

Wow,

"Gerald 300 of these bins" Sounds like you have a trash problem... hopefully your storing most of them.

I think a cyclone lid could be fit to it, I am sure it wouldn't have the same tornadic effect. I'm a Tornado Alley resident and yet to see a sqaure tornado. I wouldn't see why it wouldn't work.. the material would still DROP...

Jay

[gerald_d]

Morris put 2 bins in series - well, if I put all 300 in series, it will probably take about 10 years before I need to empty anything.
("Other" job) (http://www.mechlift.com)

[mikejohn]

Gerald
You're not the Cape Town branch of the Soprano family, are you?
....Mike

[gerald_d]

4989

[mrdovey]

Charles...

Well, it's not quite silent - but it's /very/ much more quiet than my ShopVac. If only the DC were running I could easily carry on a phone conversation (and have).

Gerald...

Why don't you try /making/ a square cyclone lid and check it out? How about adding a clear window so you can shine a light in and see first hand how well it does or doesn't work.

My dust collector bags are still cleaner on the inside than they are on the outside. I'm tempted to remove the bags altogether.

I've been thinking about building a box on top of which I can mount just the motor/impeller - then put the barrels on a shelf. If I install doors in the bottoms of the barrels, then I should be able to easily empty them into wheeled (possibly square) trash cans.

With 300 bins Gerald doesnt have a trash problem - he has a /bin/ problem (-:

[gerald_d]

Morris, I do plan on doing a lid for these bins (which are the standard all over Europe, South Africa and Minneapolis). I could arrange a circular tube, attached to the lid, that protrudes 8 - 12" below the lid - that should bluff the dust into thinking that it has entered a circular bin. Only snag is that we don't have any extractor/motor yet......

The city of Cape Town purchases 90 000 of these bins per year - you should see what their yard looks like. I sell the bins to the public at about $60 ea. - the City buys direct from the producers

[mikejohn]

This thread reminds of the Dustcart that turned up at a house, and the Dustman asked the householder "where's ya' bin', and gets the reply "On my holidays".
"No"says the dustman "where's ya' wheely bin"
"Oh" says the householder 'I've really been to Cape Town"

English joke!

[gerald_d]

Pommie joke, more likely.

From my colleagues in Redditch, they tell me that they used to talk of "empty" and "full" bins. Now they talk "This bin empty" and "This Bin Laden".

(Mike, in America a "wheely bin" is popularly called a "trash cart".)

Back to the point of this thread!....

I would agree that dust must be removed from a bit as quickly as possible - to prevent the dust particles from being being chopped up into finer pieces. Re-chopping the particles will obviously wear down a bit's edge. This is one of the factors that push one towards lower speeds rather than higher.

[mikejohn]

Has anyone gone to the lengths of blowing a stream of air directly onto the bit as part of a dust extraction/cooling system?
....Mike

[gerald_d]

Yes, often, especially for plastics. There are a lot of posts here about that. (A search on "vortex" should be interesting)

The max "pressure" at which one can suck is around 15 psi (atmospheric pressure). With a blowgun the pressure is much higher and more focussed, cleaning out the groove much better/faster than with suction. A smaller dust skirt will "focus" the suction better.

But collecting that blown-out dust then becomes the problem.

Sometimes it is useful to leave the dust in the "groove" because it holds the part in place. But this is not good for bit life.

[joe]

Mike,

Look up www.arizonevortes.com (http://www.arizonevortes.com)

We this is a small unit which pour ice cold air to the bit.