Update: Basic tweaks and Customizer option here: https://www.thingiverse.com/thing:2418507
This is a durable, clamping Bicycle Light Mount. Printed in ABS, this version has endured over 1,000 miles of pedaling along with the consequential jars, drops, crashes, etc.
Easily adjust the aim of your light. This design is meant to hang underneath the center portion of your handlebars so it's out of the way.
Measure your handlebar diameter, and the diameter of your flashlight so you can adjust these appropriately before you print.
Attach each clamp with nuts and bolts (adjust these to hardware you have onhand, if desired). Attach the pivot with 1/4" bolt and wingnut (or whatever...).
Print in either PLA or ABS, but ABS will be more forgiving on the road.