This is an end cap for a bicycle handle bar with 17.5mm inner diameter.
You need a pan head screw M4x25 and a M4 nut.
I added the Fusion 360 file. Feel free to modify according to your needs.
handle_bar_cap.stl | 150.6KB | |
handle_bar_cone.stl | 50.1KB | |
handle_bar_end_cap_complete.f3d | 144.2KB |