The last large slab I surfaced I was literally using a shovel to pick chips off the floor. Part of the problem I fixed by adding a border to the sides of my machine I do not need access too. Next I thought I would do a bit of experimenting to see if I could improve the dust collection. Using the tips from many others I increased the size of the duct to the shoe. That coupled with improving the overhead piping helped some, but it still was not great. I decided to alter the basic shoe design I had to see if I could improve it. I am pretty much stuck fixing the basic shoe design because I cannot afford (or justify) the industrial solution to chips pictured below.
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The first dust shoe I built did not work any better. In the second version I added a small housing to the underside of the shoe to get the suction side closer to the cutter. The housing was sized so its bottom aligns with the bottom of the collet. This version worked a little better, but the air velocity near the cutter was still quite low. I tried extending the housing closer to the cutter, but it did not work much better for the 3" - 3 1/2" long cutters I use. I did find this design picks up more dust than my old shoe as the tool moved around the part, but that will be largely because of the increase in the size of the piping.
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The third shoe design was similar to the second, but I added a bellows to the bottom of the shoe. The height of the bellows is adjustable, and it has two springs that keep the bellows open. A friend referred to it as a dust pan. The air velocity is much greater at the cutter when the bellows is opened, and it does seem to collect more chips. When cutting full sheets without any large pockets it should be fine to let the bellows float on top of the stock like others one can find, but I already found it needs to be adjusted to be above the stock when cutting large pockets or partial sheets where it goes past the edge of the stock.
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I am curious to hear any ideas others have to improve the shoe design. I have to cut out some sheets of plastic in the next few days so I am curious to see if it works much better. The last sheets of plastic led to far too much time vacuuming up chips.