Why do you need to do this mod?
Even if you have never broken a frame pin, this is a great modification to do to your Nano CPX. The frame does not have replaceable pins like other larger helis. This means you need a new frame. That means you need to pull it all apart and put it all back together - ugh. This method fixes the existing pin and frame and results in a stronger frame. You may even want to cut the pins off and modify them this way to prevent breaks and lost pins.
If you have already broken a pin, you will need to find the broken pin or something to replace it. Some CF rod may work, or some other plastic you can cut to fit. You can also put some hot glue on the pins to hold them in place if they ever do break. Thats what I did on this one. It was weak and ready to fall off, but I used some CA glue tho put it back on and then some hot glue to hold it in place when it finally did break off (the next flight).
Another option is to cut your pins off and perform this mod on each. It will strengthen them to prevent breaking, and if they do break it will most likely keep them from falling off.
Parts You Will Need
Prepare the pin
You will need a relatively flat surface for this to work. If it has some shape and texture that will help the bonding process with the glue, but if it is too uneven you may not be able to drill the necessary hole very easily. If you are doing this mod to an unbroken frame, cut the pins off with a sharp tool or a hot wire. Dull scissors or other cutters can compress the ends making them too small to work with.
Drill hole in frame and pin
I used this $7 drill kit from Amazon. It is pretty cheap and flimsy, but gets the job done very well. I used the size 76 bit. How can you tell what size to use? I drilled a hole in the side of the bit box and made sure the wire fit. I then scratched the size of the bit used below the hole so I can have a reference of sizes on the box.
Go slow and steady. You want a hole that is deep enough, but not crooked or too deep. If you perform this with your Nano assembled you can drill into the shaft if you are not careful. Don’t do that.
Drilling the frame
This is the hole in the frame, because I had a picture of it I figured would at least use it. Words of caution: do not drill into the main shaft, if you do go through the frame but not into the actual shaft, be careful when adding the glue, capillary action can take it down the hole and into the shaft, gluing your shaft to the frame. That will not be good. I went about 3mm deep.
Insert wire and apply glue
Put it together
Make sure the fit is tight and there isn't a gap between the plastic. If you didn't drill deep enough or used a wire that is too long you will need to put it apart and drill deeper or trim the wire.
I added a bit more CA glue around the joint to give it more support. Let it dry for a while, no sense in doing this only to break it again because you didn't let it properly dry and cure.