Cutting gear teeth: Reducing straight teeth is usually comparatively easier than trimming helical teeth. Gear milling or equipment hobbing can be used to cut the teeth of spur and helical gears. In milling, just two simultaneous motions are wanted to cut teeth of spur gears; however, three simultaneous motions are necessary for cutting the teeth of helical gear.

Effect load, vibration and sound: Since teeth of two mating spur gears comes in sudden contact, therefore they encounter a shock or influence load. This also creates significant vibration and sound, which occasionally impose limit on optimum permissible speed of procedure. On the contrary, gradual get in touch with between mating teeth outcomes a gradual load on the teeth and lower vibration and sound. Thus helical gears may be employed at higher swiftness without much problem.

Contact scenario between mating teeth: Spur gears have straight teeth parallel to gear axis. Two mating gears are also mounted in parallel shafts. Thus teeth of two mating spur gears come in sudden get in touch with and the contact is always a line of size equals to teeth face width. On the contrary, helical gears have helical teeth plus they are mounted on parallel shafts. So the teeth of two mating helical gears can be found in gradual contact. Their engagement starts with a spot and becomes a collection and then gradually disengages as a point. So contact length will not remain constant.

Orientation of driver and driven shafts: One simple advantage of gear drive over other mechanical drives (like belt or chain drive) is its possibility to use for non-parallel shafts. However, several types of gear are suitable for varying orientations of driver and driven shafts. Both spur equipment and helical gears are overwhelmingly used for parallel shafts; whereas, bevel gears can be used for intersecting shafts and worm gear can be used for perpendicular non-intersecting shafts. There exists a particular kind of helical gear, called crossed helical equipment, which can be useful for transmitting power between perpendicular shafts. This is very similar to worm gear; however, crossed helical equipment cannot provide high velocity reduction. Typically, it really is suitable for 1:1 to at least one 1:2 rate ratio (when compared with 1:15 to 1 1:100 in worm gear). Its application is also limited due to many limitations.