Vacuum
 The vacuum system was the result of a fair amount of trial and error. An ideal system would use only airflow to remove the chips and dust. However, the momentum of the larger chips requires a physical barrier to stop their throw. A small brush does this, but the brush is not needed for most work, so the bit is visible as it cuts. It helps to place the vacuum intake as close as possible to the bit. This positioning takes advantage of the router's exhaust which helps to force debris up the vac port. |
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also allows the footprint of the vac pickup to be quite small.The simple offset is made of sheet metal (A kipper tin would probably work) and a sink's 1-½" tail-piece. The brush is a split ring and easily snaps off its collar revealing the bit. It is made of paint brush bristles hot-glued to a section of PVC pipe. |
 Again, the brush is usually unnecessary when smaller bits are used. The vacuum is powerful enough to remove dust that would become airborne, though some heavier debris is left on the table. |
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The above system worked well enough, but it was ungainly and kept bumping into hold-down clamps. It was time for another approach as shown below. First measurements were made and drawn in Rhino 3D with toolpaths created in RhinoCAM. The part was CNC routed, then sawn from the block, glued together, used as a mold for fiberglass, and finally assembled and installed. |
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It was drawn in Rhino and
toolpaths were created in RhinoCAM.
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 It was then routed with the CNC machine. The halves were cut from the stock, glued together and covered with fiberglass and resin. Images below. |
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 The parts were then assembled and painted. It works well! |
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 The vacuum hose swivels from the ceiling. Parts are standard DWV (Drain Waste Vent) plumbing fittings and vacuum hose. A metal section of plumbing pipe attaches to the DWV pipe connection on the ceiling. 1-1/2 inch plumbing fittings fit well inside 1-1/2 inch vacuum hose. These are the thin walled fittings used in exposed areas such as under sinks. |
 The vac is powered by an abandoned run-of-the-mill vacuum cleaner motor. The table does not always require a great deal of suction so a speed control dials down the vac's velocity and noise level. The unit never loses suction due to a dirty bag since the cyclonic separator makes a filter unnecessary. Jetsam is caught in the mud bucket at the base of the cone. The shape of the cyclone can be within a large range when the vac is vented outside. In this set-up the cyclone's purpose is to remove the dust that could damage the impeller, not to remove all particles that are harmful to lungs. The inlet tube to the cyclone is a sweep elbow inside the funnel. This directs the chips in the direction of the vortex. It is better for this entry leg to be long to allow the chips to gather momentum so they will tend to sling around the sides. Again, since this unit is vented outside, high efficiency is not required. |
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