Air nozzle for Othermill Pro / Bantam Desktop Milling Machine

Clear chips from your work piece with this svelte blower


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I added an air nozzle to our Othermill Pro desktop CNC to clear chips away as it cuts.

NOTE: Use common sense and caution, please. Your mileage may vary. If you're making deep cuts, this could interfere with and damage your part, or get caught by the bit. Do not taunt happy fun ball.

Othermill / Bantam provides a small fan that attaches to the bit itself as the recommended method for chip clearing, but I found it cumbersome, and eventually the fan didn't fit tightly on the shank of the tools anyway.

I installed a push-to-connect fitting that mounts through the wall (yep, you've gotta drill through the housing of your mill) so you can easily connect or disconnect air without reaching in the machine. The air hose is routed along the existing cable runs to keep it out of the way, and has a Luer-lock fitting so you can swap in different nozzles if you like. It mounts to the carriage using existing M3 tapped holes (PEM inserts, actually) so no drilling/tapping needed on that end of things.

I happen to have M5 and 1/4-28 taps, as well as the 4 mm tubing on hand since we use these parts a lot at work, but it'd be easy enough to swap in all Imperial unit parts instead, or use narrower tubing, etc. Modify as you like!

Materials and methods

Bill of materials:
- 1x Luer-lock fitting (
- 1x Stainless 2" long dispensing needle (
- 1x Right angle push-to-connect fitting for 4mm tubing (
- 3' (plus minus) 4mm OD tubing (
- 1x 4mm x M5 push-to-connect fitting (
- 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.



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E652303bd8dcbb024ae266d80e668439?default=blank&size=40Dave Z published this design ago