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 less aggressive 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.  It
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 removes dust that would become airborne, though some heavier debris is left on the table. This system works well enough that the smoke that results from moving at the improper feedrate is not noticed. This indicates that even the tiny particles are being removed fairly well. ...........
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. 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! In the right image, the black knob in the yoke, at the junction between the gray offset and white pipe, loosens to permit the entire assembly to be removed for bit changes. ........... |
The above system is nice, but it takes a lot of time to build, and it can be damaged by slamming into hold-downs.  For the Porter Cable and DeWalt trim routers a simpler disposable system was developed that can be made of an oval container such as a ketchup or salad dressing bottle.  |
The bottle's bottom is cut from the container, and holes are drilled, cut, or melted into the the bottom. A 1-1/2 inch hole accepts the sink tail piece, and a 7/8 inch hole fits around the collet. The tail piece is held to the router with a zip tie, as shown above. Tape attaches the bottle bottom to the tail piece.  The bottle is held to the base of the trim router with a #8 screw and washer, circled in red on the right. There is an existing hole in the base of the router that can be tapped for the #8 screw, below image. (The hole can be tapped with the base attached to the router.)  What is now the bottom edge of the plastic bottle is cut in strips that serve as flexible bristles to contain the chips and to help focus the vac's suction. This cheap and dirty, cheap and cheerful, system has proven to be very capable, and when the unit is damaged, as is inevitable for most of us, it can be quickly and inexpensively replaced. |
 In the for what it is worth department, Stanley Black & Decker is the parent corporation of the Porter-Cable and DeWalt brands, and there is obviously cross fertilization going on in the product line. The Porter-Cable and DeWalt laminate trim routers are similar and share some part numbers. DeWalt markets to professionals, and it appears they charge a premium for yellow plastic. The two units have served well in this shop. On a CNC table the routers will run long hours, and the bearings may need to be replaced at some point. They are easily accessible, and are standard sizes that can be purchased from most any bearing supplier. The bases of the routers can be reinstalled in different positions than they were in originally. This permits the screw hole for the base attachments to be rotated so the cord and switch of the router are away from the CNC machine's Z carriage. A 1/4-20 bolt can use the screw hole to tie the router to the carriage. Rotating the base can eliminate the need to buy or fabricate a special bracket to accommodate the position of the base's screw hole. The plans give directions for this alteration, but it is a straightforward process that does not require disassembly of the router. ........... |
 The vacuum hose over the 4x8 ft table swivels from the ceiling. Parts are standard DWV (Drain Waste Vent) plumbing fittings and vacuum hose. A metal elbow section of plumbing pipe swivels in the DWV pipe connection on the ceiling. This is the same plumbing fitting as is used underneath many kitchen sinks; the locking nut is left loose so the elbow can move with the hose. These 1-1/2 inch plumbing fittings fit well inside 1-1/2 inch vacuum hoses. These are the thin walled fittings used in exposed areas such as inside bath and kitchen cabinets. ........... 
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 of the cyclone and thus be better separated. Again, since this unit is vented outside, high efficiency is not required and the sweep elbow serves well enough. |