Drone prop washers

I recently made a set of aluminum prop washers on my MPCNC Primo, and figured why not share some pics?

Finished washer, ready to fly:

What for? I recently designed and built a “heavy lift” drone using some extra parts I had laying around for over a decade. Some of those parts included a set of nice of 4x Turnigy Multistar 4822-690kV motors. Since I was missing some parts for the build, and didn’t care so much about keeping it full on retro, I decided to purchase modern versions of anything I needed. One of those items was a nice set of 14" carbon fiber props. Those props use a now standardized mounting pattern found on most modern heavy lift copters; they have a pair of M3 bolts spaced 12mm apart, with a 4mm hole through the middle for centering on the motor shaft. These style of props are usually held on with a large aluminum washer that has 3 holes drilled out. Unfortunately the motors I had predated such props, and so they did not come with said washers. Instead these motors just came with a prop adapter that bolts on with 4x M3 bolts, and has a larger shaft with a single nylock nut intended for classic style single hole props.

Old school motor with a 3mm shaft and no 3-hole washers (they are very smooth and efficient even by today’s standards):

Unfortunately, nobody manufactures these washers with a 3mm center hole. Fortunately, the motors happened to have a pair of M3 bolt holes spaced exactly 12mm apart. So I figured my cnc might be able to save me from having to buy new motors just to have the right washers. All I needed was to design and mill some fairly simple washers, and figure out some bushing for the center hole. I already had some scrap 3mm" thick aluminum sheeting on hand (actually the alum stock was the Y gantry from my upgraded anet a8 printer, lol). So I drew the washers up in f360, and went to town on my MPCNC Primo after using flyfishers excellent PP to produce the gcode.

Done milling on the primo and ready for post processing (next to a pile of 1mm bits broken in the process):

As usual, the primo had no issues with the cut. I was able to use a 1/8" 2-flute upcut for the facing, 2d contour and tab operations. I switched to a 1mm burr for the 3mm holes. Of course, those holes took a few hours total to cut, and I still went through more bits than planned, thanks to the very delicate bit I used and forgetting to save cut parameters last time I used them. Regardless, they came out dialed as far as dimensions. Just a little debur and finish work (sanding off the facing marks), and they were ready to go. The fit on the 3mm shaft and M3 bolts was perfect.

Post processed washers (extra set with 4mm center holes for possible future use):

Next I had to solve the other minor problem; find or make some 3mm-4mm bushings for the center hole.

4mm hole w/ a 3mm shaft (this won’t fly well at all):

To solve this problem, I found some brass tubing that had the exact dimensions needed. I simply cut and deburred some pieces of 3mm ID 4mm OD bushings out of this brass tubing. These get slid on to the shaft, the prop gets slid over them, and the washer holds it all in place.

Complete prop mounting hardware kit:

Brass tubing happened to be a nice fit for this:

At the end of the day, the thing did end up flying, and it flies very nicely actually. For those who are curious about the drone; I’m running the latest arducopter on a holybro h7 mini, 3 axis hakrc gimbal w/ gopro and 2nd fpv cam (tx video switcher installed), servo operated payload drop, 6x lidar, optical flow, 2x4s5000mah lipos, and no less than 4x antennas (5x if you include the gps). It is a very capable utility rig, and it looks like the proverbial mother ship next to my freestyle rigs.

Thanks for looking… cheers!


Nice quad build

I built a TBS discovery photography rig maybe 8 years, back when quads were just getting off the ground (lol!!!). It’s 24” shaft to shaft, runs on a dji box, full analog 5.4ghz FOV with home made goggles… I could get 35 minute and 1.75 MILES out of that thing, carrying my canon T4i

Then we moved to a new place in a class B airport zone, and calling up the tower whenever I wanted to fly got old fast.

Then life caught up and kid#2 stripped my free time to 0.

It’s sitting in the hard case, in the basement. I should dig it out and get it tuned up. Doubt the batteries are any good at this point, but that was a fun hobby.


Can we get a full view of the quad?

I never got into the freestyle stuff- I was heavily into photography and photogrammetry. I feel like the freestyle is better done with some friends, so you can show off skills and tricks. I don’t have any, so…

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That is exactly where my fleet was last winter. I decided to give them another go with all the modern tech out these days, and found myself full on getting bit by the bug… again lol! Part of what makes quads so fun for me, is there are a ton of items that need to be designed/buit/fabricated to build and operate them. Operating quads will definitely keep a 3d printer and cnc busy hehe.

I did have to buy a bunch of new packs, but some older ones were still fine for goggles etc. A handful of my old Thunderpower lipos still fly decent after 10yr of storage… very high quality stuff indeed.


Not the best images sorry… they were quickies intended to be icons on the tiny touchscreen on my tx. It is still pretty much the same currently, but I did swap that 433 dipole for telemetry out with a groundplane antenna. It’s nice having so much room and payload capacity where I can use whatever antennas or whatever else without much thought. I’m in the process of building/tuning ground plane antennas for the 2.4 diversity rx too. Anything works work way better than those stock elrs dipoles.

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dude, nice rig. ill dig mine out later and share pics.

Ive debated getting a license and doing commercial, but I like the woodworking too much and dont want to dilute my effort.

im on a FrSKY taranis/ XR8 combo, 2.4, but it has plug and play telemtery sensors, and Aux controls. i have it shout my milliamps and heoght, speed at me every 30 seconds, lol. onboard dji telemetry through the goggles is basic but works

I seriously pulled my Mavic Air 2 out over the weekend after a year of not using it. Flew for a while, got overconfident and torched the propellers on a chair (bottom… dont ask).

I have wante to build my own for a while. I have like 4 helicopters that I want to scavenge parts from radio wise if I can but they are those Blade helos. They probably are useless for anything else.

I am an absolute noob with a DJI Mini 2. It’s working for me. :stuck_out_tongue:

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