I'm trying to connect a stepper motor with a 5mm shaft to a 1" diameter tube in order to create motorized shades. The normal attachment for non-motorized shades is basically a gear that slides into the tube (the tube has a small indent inside). How can I connect a smooth stepper motor shaft to a 1" diameter gear? I'm planning on 3D printing the part so it can be modified.
File a flat into the shaft? Use a hexagonal grub-screw collar? Drill a transverse hole through the shaft
and use a roll-pin?
Filing a flat is simple, but a 3D printed part will not be able to handle much torque at that radius, note.
If the shaft is hardened you might need a grinding wheel to create the flat. A very small flat should be sufficient.
IIRC the brass inserts in the large sized electrical chocolate-block connectors have a 5mm bore and come with screws. They should be adequate for slow motion but they probably would not be perfectly concentric.
...R
Remember also there is a product called Loctite (different strengths, semi permanent, metal to metal, may need to add a brass bushing to plastic components).