Split gearing, another method, consists of two gear halves positioned side-by-side. Half is fixed to a shaft while springs cause the other half to rotate somewhat. This escalates the effective tooth thickness so that it totally fills the tooth space of the mating gear, thereby eliminating backlash. In another edition, an assembler bolts the rotated half to the fixed half after assembly. Split gearing is normally used in light-load, low-speed applications.
The simplest & most common way to lessen backlash in a pair of gears is to shorten the distance between their centers. This moves the gears into a tighter mesh with low or actually zero clearance between the teeth. It eliminates the result of 
variations in center distance, tooth dimensions, and bearing eccentricities. To shorten the center distance, either modify the gears to a fixed distance and lock them in place (with bolts) or spring-load one against the additional so they stay tightly meshed.
Fixed assemblies are typically found in heavyload applications where zero backlash gearbox reducers must invert their direction of rotation (bi-directional). Though “fixed,” they may still require readjusting during support to pay for tooth wear. Bevel, spur, helical, and worm gears lend themselves to set applications. Spring-loaded assemblies, on the other hand, maintain a continuous zero backlash and are generally used for low-torque applications.
Common design methods include short center distance, spring-loaded split gears, plastic material fillers, tapered gears, preloaded gear trains, and dual path gear trains.
Precision reducers typically limit backlash to about 2 deg and are used in applications such as instrumentation. Higher precision models that obtain near-zero backlash are used in applications such as for example robotic systems and machine tool spindles.
Gear designs can be modified in several ways to cut backlash. Some methods adjust the gears to a established tooth clearance during initial assembly. With this approach, backlash eventually increases due to wear, which needs readjustment. Other designs make use of springs to hold meshing gears at a constant backlash level throughout their provider life. They’re generally limited by light load applications, though.