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

Influence load, vibration and noise: Since teeth of two mating spur gears comes in sudden contact, therefore they encounter a shock or effect load. This also creates significant vibration and sound, which sometimes impose limit on optimum permissible speed of procedure. On the other hand, gradual get in touch with between mating teeth results a gradual load on the teeth and lower vibration and sound. Thus helical gears can be employed at higher velocity without much problem.

Contact scenario between mating teeth: Spur gears have directly teeth parallel to equipment axis. Two mating gears are also mounted in parallel shafts. Thus the teeth of two mating spur gears can be found in sudden get in touch with and the get in touch with is always a line of length equals to teeth encounter width. On the contrary, helical gears have helical teeth plus they are mounted on parallel shafts. So tooth of two mating helical gears come in gradual contact. Their engagement begins with a spot and becomes a range and then gradually disengages as a spot. 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 nonparallel shafts. However, several types of gear are suitable for different orientations of driver and powered shafts. Both spur gear and helical gears are overwhelmingly used for parallel shafts; whereas, bevel gears can be used for intersecting shafts and worm equipment can be used for perpendicular nonintersecting shafts. There exists a particular type of helical equipment, called crossed helical gear, which can be employed for transmitting power between perpendicular shafts. This is quite similar to worm equipment; however, crossed helical gear cannot provide high velocity reduction. Typically, it really is suitable for 1:1 to 1 1:2 quickness ratio (when compared with 1:15 to at least one 1:100 in worm gear). Its application can be limited due to many limitations.