Best Times to Go to Florence, Italy. Avoid summers if you can, it's hot and packed with sweating tourists in July and August. That said, there's hardly a time you won't encounter tourists in Florence. If you must go in summer, make hotel reservations early.
Helical. Helical (adjective) is having a spiral form of many rounds. Helical can be a hairstyle curl, loop fold of a ribbon that serves as pony and a repeated dialogue of an actor that gives twist to the audience.
An involute helical gear is the base pitch in the normal plane. It is the normal distance between parallel helical involute surfaces on the plane of action in the normal plane, or is the length of arc on the normal base helix. It is a constant distance in any helical involute gear.