Helmet mounted bicycle light on the quick and cheap!

Step 5 Securely mounting metal to plastic?

This may seem a bit daunting and it is, so I didn't even consider it. The flashlights I bought conveniently had some ridges machined into the body. Ridges which I realized would easily keep rubber o-rings in place. I actually used o-ring shaped garden hose washers but any local hardware store will have a large variety of sizes to fit whichever flashlight you decide upon.

Two fore and aft ensured a nice interface between the light and the plastic helmet skin. See photo for before/after.