After messing around with bearings and magnets and spending lot of time to get those complicated stuff to fit together I was not happy with all that stuff. So I went back to a much simplier design, where no bearuings and no magnets are needed. Tension comes just from the plastic and so all you need is the 3 parts printed out, 2 pins (nails in my case), some wire, the female part of a 7mm bullet plug (I used this, because I have plenty of them in my spare parts box from unsoldering it from LiPos). If you want to be able to adjust the gap, you need 2 pcs. of M2 bolts. I used one from left overs I have tons from helicopter built.

In the pictures you see all you should know for putting it together. If you want it a little bit cleaner, you can use epoxy instead of hot glue. I prefer hot glue, but it's a bit of a mess with the strings you get. After all is put together, you do not see it though.

For connecting it to the keyer or your rig, you can use an audio cable with a 3,5mm plug, if you use a socket, like I do. You can see that on the pictures. You could also just solder the cable directly to the pins and the center piece. Then just put the cable through the whole in the case, before you solder it together ;-) and don't forget some kind of strain reliefe (cable tie and/or hotglue/epoxy, etc.)

For me that paddle works amazingly well. I do not have any longtime experience though. Printed it in PLA so do not use when it is hotter than 60C. ;-)

Other than you see on the fotos, I made a little change to the design of the case. Ther is a slot where the center pin fits tight into it. That is to avoid pushing the center agains the opposite contact, when working with a very tiny gap.