Reduce dust from your radial arm saw
The first step is to determine what kind of cuts you usually make. Do you use it for cross-cutting (i.e. 90 degree cuts) with your hood set up as shown in photo 1? Or do you use it for mitre cuts with your hood set up as shown in photo 2? You will also need to consider the shape of the saw guard, and the maximum travel of your saw past the fence.
The second step is to block off the small dust port that the manufacturers have molded into the blade guard of your particular saw. This will ensure maximum efficiency of the dust collection system that you custom design for your saw.
Now, contour your chute to the saw, curving the base of the chute up, to guide the sawdust toward the collection pipe. Form the top of the chute to hug the saw when it is parked. Keep the chute small, to help maintain a high velocity inside the chute. The rear of the chute is only 4″ wide. Make the front of the chute wider.
This configuration draws more surrounding air into the chute and helps to capture the sawdust, as the saw moves away from the chute. Determine the path that the piping will take, and make sure that you will be able to operate the saw’s adjustment cranks.
Note the pipe direction in the photo below, it just clears the operating crank at the wall.
This type of chute only works well if you are making straight cross-cuts. In the photo below you will see a chute that was built and modified for a saw that is being used for mitre cuts and straight cross-cuts.
The wing on the right, in front of the post, helps to direct the sawdust into the chute. For this set-up, the height of the wing should not interfere with the downward travel of your saw’s arm. Notice also that the front opening is larger, to accommodate left and right angle cuts.
The owner of this particular radial arm saw also uses it for ripping, so the rear chute won’t be of any help for collecting dust during such ripping operations.
Fortunately, this saw has an adjustable front blade guard plate, so I was able to utilize the same hold down knob to attach the new modified pick-up. The photo below shows the right side of the pickup.
Notice the nylon brush along the leading edge of the pickup. This brush helps to contain the sawdust as it is fired forward and up by the blade. The photo below gives you a better look at the left side.
Notice that the original opening is blocked off, and that the plastic blade guard is still in place. Do not disable the factory safety guards when you build your pick-ups.
This particular pick-up is made from 20- gauge body steel, a few inches of nylon brush, sealing strip, and pop rivets. The port is an after-market plastic band saw port. This pick-up will not work for ripping and cross-cutting, especially when the wood is 1″ thick or more.
When cross-cutting, the blade shoots sawdust through the saw kerf and beyond the brush. Instead, use your rear chute when cross-cutting. Even with the special pick-up for ripping, you will still loose some saw dust as you finish cutting through the end of the board.
Model your chute with cardboard and duct tape. Your model must be smooth inside, in order to guide the sawdust to the outlet pipe. Keep fine-tuning, until the model works correctly, before you actually construct your dust collection system of metal. It will save a lot of wasted time and materials, and ensure that the end result is what you want and need.