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

Impact load, vibration and sound: 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 noise, which sometimes impose limit on optimum permissible speed of procedure. On the other hand, gradual contact between mating teeth results a gradual load on one’s teeth and lower vibration and sound. Thus helical gears can be employed at higher rate 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 tooth of two mating spur gears come in sudden get in touch with and the get in touch with is always a type of size equals to teeth encounter width. On the contrary, helical gears have helical teeth plus they are installed on parallel shafts. So tooth of two mating helical gears come in gradual contact. Their engagement starts with a point and becomes a line and then steadily disengages as a point. So contact length does not remain constant.

Orientation of driver and driven shafts: One fundamental advantage of equipment drive over other mechanical drives (like belt or chain drive) is the likelihood to use for nonparallel shafts. However, several types of gear are ideal for various orientations of driver and powered shafts. Both spur equipment and helical gears are overwhelmingly used for parallel shafts; whereas, bevel gears can be used for intersecting shafts and worm equipment can be utilized for perpendicular nonintersecting shafts. There is a particular type 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 gear cannot offer high velocity reduction. Typically, it is suitable for 1:1 to at least one 1:2 quickness ratio (when compared with 1:15 to 1 1:100 in worm gear). Its application can be limited because of many limitations.