im thinking that the pin failures might also be down to the grub screw method of locking the gearbox. When this is used, the ring gear will spin ever so slightly until the notches hit the screws. These slight but sudden stresses cant really do much good to anything that isnt effectively secured i.e. the pins.
In theory, could you silver solder the pins in?
Also, any tips for removing robo challenge wheels from the output thread when its been on there for years with a sh!t load of loctite?
Bookmarks