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.
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.
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.
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. ras4.jpg
Comments; questions; duplication perfectly welcome.