Best Radial Arm/Miter Saw Dust Collector yet

[Ben Hatcher]

I've tried several iterations of dust collection/chip collection for my radial arm saw and have never been very pleased with any of them until now. This latest version works perfectly and was very easy. I use my RAS primarilly for cross cuts and I knew that I wanted the new top to be part of a larger workbench. What I did won't work as well if you use your RAS to make lots of angled cuts unless you make the table deeper.
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Background:
My old collection technique was similar to many I've seen here. There was a box with an angled plate that deflected the chips down to an opening where they were sucked up. It got most of the chips, but not all. I figured I could do better so I watched where the uncollected chips came from. I noticed that the majority of chips traveled strait back from the bottom of the cut, along the kerf, and into the collector. Since the kerf stopped before the collector, chips actually flew up from the table, hit the deflector plate, and for the most part fell down to be sucked up. Some, however, bounced off and escaped collection. When making a non-through cut, the problem was the fence. The cut was not deep enough to bury the gullets. Chips escaped the cut, traveled back along the work piece until they hit the fence and were scattered. Because the collector was so far back, there wasn't sufficient airflow to draw all of the errant chips into the collection slot.

The solution to this seems obvious.

Use the natural flow of the chips along the kerf.
Make a lower fence so that chips from non-through cuts weren’t interrupted in their path to the collector.
Bring the collector as close to the fence as possible.

Here’s step one and two. It works perfectly.

As I said, I wanted the saw to be built into a larger bench so I bolted a board to the wall and hung a shop made RAS stand to it. I enclosed the bottom of the saw with a piece of hardboard and cut a 6” hole in the back left corner where the chips would be collected.
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The blast gate is located just under the table in this location as well. I cut the new top/workbench to accommodate the saw tower and made an opening 4”x6” to match the area of the 6” DC pipe. I used some scrap laminate to build a ramp from the front of the saw towards the DC opening so that chips would not collect within the saw base. (more on that later) The saw was bolted to the work surface from the bottom using the same flanges as the factory top. I aligned the fence to the blade and glued and screwed the fence to the top. I then cut all of the way through the fence and table top stopping just short of the base. I then raised the blade to just under the thickness of the melamine and finished the cut.
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If you think about it, I basically turned the RAS into a table saw as far as dust collection goes. Chips can now exit below the table, in the direction they want to travel in the first place. I tested the design prior to attaching the hood and it works perfectly. No chips escape. I don’t even know if I need a hood, but I plan to build one anyway. This is the concept: front will be even with the front of the fence, wide enough to allow 45’s to be cut in both directions, and will angle back towards the collection point. It will be low profile so that the motor housing clears it with an 8” dado blade installed. 209292

Comments; questions; duplication perfectly welcome.

[Aaron Berk]

Well your results sound commendable, but I would be worried that with such a huge saw kerf you might have compromised the integrity of the table.

I think a thicker table, or a 3/4 sacrificial top would be in order.

I like the DC up through the base.

[Ben Hatcher]

The top is actually pretty solidly attached to the saw. There are 8 bolts connecting the two on the underside of the table. Each half of the bench is screwed into the ledger board which is bolted to the wall. Additionally, one of the screws holding the fence down goes through the frame of the saw base. I'm not sure what a sacrificial piece would do to the collection. I think if the kerf did not go all the way through the table it would clog. I had initially though of running a pvc tube between the two halves that made up the original top. This way seemed better/easier.

[Aaron Berk]

Got it :)
I had assumed the saw table was bolted in conventional Craftsman RAS fashion.
From the photos it looks as if the front of the table could get a little floppy.

If you used a sacrificial top then the integrity of your table would stay in tact, and only the top board would get the "full kerf" treatment.
And from the pics it doesn't appear that the kerf fully splits the two pcs?

[Ben Hatcher]

The kerf fully splits the two sides up to the point where the base of the saw begins and the cavity ends. I didn't want to risk ruining my blade hitting the metal frame. The support brackets that connect the original top are used to connect this top. I still have some edge banding to add to the table which will provide a bit more rigidity at the edge, but in reality, the bolts are maybe 2" from the edge as it is. It is pretty solid.

Here's the final piece, the upper dust shroud. It ended up being a little more shallow of a slit than I had hoped, but it works perfectly. It gets all of the dust, even from very shallow dados. The only time it isn't ~100% effective is on a cut where one side of the cut is open. Even then, it is 99%+ effective.
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The two inner supports keep the sides from bowing down when the DC is on. My airflow is reduced more than I wanted. I suppose I could drill a few holes in the top to fix this should it prove to be a problem.

[Aaron Berk]

I like it Ben, good job.

My RAS has yet to get the DC treatment, and it's killing me.

[Dave Mura]

Nice job!
http://chdsolutions.com/img/11d867796d85db8cad5280ac44cec7c1.jpghttp://chdsolutions.com/img/a57d48399922b03419153a9760c5ce53.jpghttp://chdsolutions.com/img/beda24c1e1b46055dff2c39c98fd6fc1.jpg

[Jim O'Dell]

Very interesting concept! I will be playing with this some. Jim.

[Cyrus Brewster 7]

That is a really cool idea. I am about to start the process of putting DC on my CSMS station. I will have to rethink some of the design - the main difference being the larger built in fence.

Thanks for sharing.

[Chris Parks]

What sort of DE is attached to the hose? With enough power you get this http://www.youtube.com/watch?v=8AIITfs51PE&feature=player_embedded which I would think gets most if not all the dust practically possible. Any chance of seeing a video of your idea in action?

[Ben Hatcher]

@Cyrus it seems to me that the concept of collecting the chips from the underside of the cut would apply to a scms as well.

@ Chris: my dust collector is a delta 50-760 with a wynn filter and a super dust deputy. As you can see in the first picture, I blocked off the port on the blade guard and no longer use the hose. In my tests, nothing came out of the hose and it was constantly getting in the way.

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My pipes are all pvc because I like to live dangerously.:eek:

More power would be nice, but this design doesn't rely on brute force to wrestle back stray chips. It uses the chips natural momentum to aid in their collection. It is almost like the chips collect themselves and all the DC does is help them continue on their way. I'll try to post a video so that you can see what I mean. This actually has me wondering how well this setup would work without any external suction.

[Chris Parks]

I think it is fairly easy to collect the chips etc off a miter saw these days as a fair few systems have been designed which seem to work. What we might be missing out on is the spray of fine dust and for that you need a lot of air flow at fairly high speed as in the video. Most of us think that if we clean up the chips and debris we can see then it is a job well done but that is not the case. We need all the micron sized dust or as much as possible to also be captured, filtering the air is an after event band aid which should only be used to catch the dust which is beyond our capacity to capture at source and there will always be some of that no matter what we do.

[Kent Parker]

Ben,

I have on numerous occasions used my RAS for dadoing and the amount of dust flying off just about killed me until I boxed in it in. My saw is dedicated cut off or dado only, no angles.

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Intake is at the underside with glued in pieces of 1/8" plywood to act as a directional funnel towards the intake. Works great.

Cheers,

Kent

[Dave Zellers]

Love seeing the ancient Craftsman RAS. I have the same model although it is secondary to a newer model that I use daily.

[Ben Hatcher]

Here's a video of the dust shroud in operation. I cross cut some 4/4 poplar and pine, some 16/4 african mahogany, and did some cross cuts and dados in pine and mdf. As you can see, the chips are all collected and there are no dust clouds. This is the "capture at source" that Penz advocates. I couldn't agree more. If you need to dado thicker pieces, you should make the shroud taller. I think that this is the best collection technique for a radial arm saw and I also think it is adaptable for most miter saws, too.

http://www.youtube.com/watch?v=YRFjRvQTckM

[Chris Parks]

Ben, it seems to work well and if you are happy with it then that is the important part. I have not got an RAS to build the same thing and a mitre saw works differently in that it has a high fence as part of its structure with the support for the saw head that deflects the dust and gets in the way generally. I guess a RAS is more controlled in its ejection of the chips and dust and easier to get a good collection. Thanks for posting the video.

[John T. Reagan]

How does this work on angled cuts now that you have the hood on it?

[Ben Hatcher]

I don't use this saw for angled cuts. I made the decision when I built it that this would be a dedicated cross cut saw. If I were to change my mind, I'd need to either make the top of the hood out of a thicker material that could stand up to several kerfs cut in it or make several of them to use with different angles.

The bigger issue is the fence. Right now, it is just screwed and taped in place. Allowing a variety of angles to be cut with this set up would require the fence to be glued in place. For whatever reason, I'm not ready to make that committment.

The only part that isn't compatable with angled cuts is the "through the top kerf" because miter cust pass over frame members in the saw base. I toyed with the idea of cutting common angles with a dado blade then laminating over them with some formica to make dust channels. I'm not entirely sure that those would be necessary. Because of the way a radial arm saw works, most of the chips seem to stay within the kerf so the rear collection point and slightly raised hood opening would probably be suffucient.