Bill of materials: - 1x Luer-lock fitting (https://www.mcmaster.com/#51525k221/) - 1x Stainless 2" long dispensing needle (https://www.mcmaster.com/#6710A24/) - 1x Right angle push-to-connect fitting for 4mm tubing (https://www.mcmaster.com/#5225K12/) - 3' (plus minus) 4mm OD tubing (https://www.mcmaster.com/#50315k68/) - 1x 4mm x M5 push-to-connect fitting (https://www.mcmaster.com/#7880t368/) - 5-6x small zip ties - 2x M3 x 10mm screws - 2x M3 lock washers Before you begin, use the software to move the mill into the "loading" position. This ensures that you won't drill through anything important. Now, TURN OFF THE MACHINE and UNPLUG IT. No drilling / monkeying around while it's on, please. 3D print one FittingBlock (I used .15 mm layer height, 25% infill, and 0.8mm walls). Tap one side with M5 threads and the other with 1/4-28 threads. You'll probably want/need a bottoming tap for this operation, since the diameter is bigger than the M5 hole. Then attach the two fittings (4mm x M5 push-to-connect and 1/4-28 luer-lock) to the FittingBlock. Drill a 10 mm hole through the left-hand side of the mill. The hole should be positioned 45 mm from the back edge and 80 mm up from the bottom. Insert the right angle, thru wall fitting with the elbow on the inside. Next, insert one end of the 4 mm tubing into the fitting (on the inside of the machine). Run the tubing along the existing cable runs, using zip ties to attach it. No need to cut the existing zip ties. Once you get to the back of the X carriage, run the rest of the tubing up and over the carriage. Remove the right-hand window, and attach your assembled FittingBlock to the *upper* right-hand side of the carriage using the M3 screws and lock washers (important, since this will see a decent amount of vibration). If you install it using the lower screw holes, the nozzle will likely be too long and will interfere with your part or (worse) the tool bit. Finally, attach the dispenser needle to the luer-lock fitting and bend it to direct the airflow. You don't need much air flowing through to clear chips. I use a cheapy Harbor Freight airbrush compressor set at 20 PSI, give or take.