- Gears, Differentials, Racks & Pinions
- Synchronous Drive Belts, Pulleys, & Cables
- Couplings, Flexible Shafts, & Universal Joints
- Chains & Sprockets
- Shafts & Shaft Accessories
- Bearings & Linear Motion Components
- Motors, Gearheads, & Motion Control
- Speed Reducers & Right Angle Drives
- Hardware
- Miscellaneous Components
- Linear Guide Systems
- Clutches & Brakes
- Vibration & Shock Mounts
Gear Racks
A gear rack is used to create linear motion out of rotary motion. Gear racks have square or round shafts with straight, equally spaced teeth; a pinion gear’s teeth mesh with the teeth of the rack. We combined as a unit they are referred to as a “rack and pinion”.
Gear racks are used in a variety of applications, and it may be necessary to pair them for length. Pairing can be accomplished by having racks with matching machined ends. They can also be modified to contain mounting holes. Racks and pinions are found in lifting and positioning systems where vertical or horizontal linear movement is necessary. They are commonly found in steering systems for vehicles, lathes, packaging machines, depth and height gauges, elevators, gates, stair lifts, and pneumatic actuators, to name a few.
Our inch and metric gear racks are available in steel, stainless steel, aluminum, nylon, and plastic in a variety of finishes and heat treatments, in pitches ranging from 120 to 1/20 and modules from 0.3 to 10.
Ball Screws vs. Racks
Because there’s no limit to a rack’s length, coupled with their heavy-load capacity, gear racks can be used as an alternative to ball screws. Ball screws are mechanical actuators that utilize a helical screw and nut to transfer linear motion. Ball screws can also be utilized for their heavy load capacity and high precision. A ball screw is limited by its length and how much it will compress under a given load (known as deflection). Racks and pinions are both susceptible to backlash (more on backlash here).
Calculating Mounting Distance
To calculate the mounting distance for a pinion and rack, you must divide the pitch diameter of the gear by two and add the results to the pitch height of the gear rack. Illustrated in the equation: