Mounting a Single Light on Top of the Helmet
If your helmet has two vent holes aligned on the top, this method or a variation of it, will allow you to mount a light on the top of the helmet so that the beam is aimed properly. A small block of polyethylene foam is cut with a razor knife so that the bottom conforms to the helmet curvature and the top has a shallow V to hold the light. The bottom of the foam has a piece of inner tube flattened and contact cemented (similar to this) to the foam to provide suitable friction with the helmet to prevent the light from shifting. Two lengths of elastic, in this case strips of inner tube, are passed from the inside of the helmet, through the two holes, front to back, with the ends coming out the top of the helmet. These two elastics are crossed in an X pattern, left to right and right to left, and tied on the top of the light. Double tie the top elastic. This method of foam and elastic has been found to be one of the most simple and lightweight ways for mounting lights. Just carve the shape needed.