DJI F450 adapters for 0.5" X525 aluminium arms

Warning!

If you are using the type of landing legs in the pictures (DJI landing skids), use all four screw holes! Depending on the frame, you may have to drill these holes. The landing legs will otherwise act as a lever when landing and eventually tear the adapters apart. This also happens on original DJI arms, but not as quickly, as they are injection molded.

Update 29.01.2015:

All versions updated. Designed my own rear part of it (no longer taken from another source), made it slightly lighter and easier to print. There will be a 1-2 layer thick ceiling in the opening at the back now. You can either leave it or cut it out, the main purpose is to avoid ABS curling on the arc. Print with brim if you still have issues. No support needed.

Update 23.01.2015:

Knurled version updated again with slightly larger holes.

If plastic rises into the screw hole of the knurled nut, use a 2mm metal drill to carefully drill out the hole again. Try not to touch the metal thread with it and dust off the drill bit regulary to allow it to transport the plastic.

Update 18.01.2015:

All models updated. There is now a 1-2 layer thick cover on the inside 4mm hole. This will allow the printer to use bridging rather than sticking a hard-to-remove support into the square hole. So these will now print without support and end up with a cleaner inside surface. Stick a screwdriver in there and the layer will easily break apart to open up the hole. You still may have to file the square holes open a little depending on your printer calibration.

Also added: "Knurl" version of the spare arm one. This one is meant to be used with metal inserts like these: http://www.ebay.com/itm/251716998095

Melt them into the four main holes with a soldering iron. The rear two holes don't have space for threaded inserts, as they only give some extra support anyways.

Test flight was successful, the arm adapters work fine.

I bought a nice "alien" type frame that uses the DJI arms, but don't like the plastic arms for various reasons. So I created my own adapters to fit the X525 quadcopter frame arms (0.5"/13mm), based on the rear part of dirkdirks F550 arms. Not flight tested yet due to weather, but they feel very sturdy and hold the arm firmly.

The aluminium arm is replacable by just releasing one screw, if one is bent.

"Spare" fits the clone arms (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=40663).

"Stock" should fit the original X525 arms which are slightly larger all around. This is currently untested, however.

I printed them in ABS, 50% infill, with brim (to prevent the thinner loop part from lifting) and sliced with Slic3r. Support is needed around the M4 hole.

The screw holes are undersized on purpose, so a metal screw will cut its own thread. The end of the adapter will stick out from the center plates some, this is pretty much unavoidable to give the arm enough support. An M4 screw holds the arm in place. It'll be a bit of a tight fit, which only adds to the stability.

Requirements per arm:

4x M3x10 screw (2x M3x10 and 2x M3x16 if you want to use the landing gear from DJI as pictured)

2x M3x12 scew

2x M3 lock nut

1x M4x35 screw (I originally used 30mm, but have to turn the lock nut around then)

1x M4 lock nut

2x M4 washer

6x M3 washer

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