Front rack to support Topeak Fronloader bag. Without this support, the bag is wobbly and bumps into the frame or the wheel. It was also problematic with my vintage cantilever brakes.

Depending on your printer settings and the steering bar diameter you may need to adjust tolerances of the clamp or stick a thin stripe of rubber between the rack and the bar.

Clamp holes are designed to be used with CNC Kitchen 5x5.8 threaded inserts. 

Original design in onshape.