When a stepper motor is positioned parallel to the indexing table, which drive is commonly used between them?

The commonly used drive between a stepper motor and an indexing table positioned parallel to each other is a worm gear. Worm gears are well suited for applications that require precise positioning and stability. They provide a high torque output with the capability to reduce speed, which is essential when controlling the movement of the indexing table.

In scenarios where the stepper motor needs to drive an indexing table, having the worm gear ensures that there is minimal backlash, allowing for accurate positioning of the table. The gear ratio can be tailored to achieve the desired torque and speed, making it advantageous in applications requiring exact movements.

Belt drives, while useful in transmitting power over longer distances and allowing for some flexibility in alignment, typically introduce more backlash and are not ideal for precision applications. Chain drives share similar limitations in precision and are more suited for higher speed and lower torque applications. Direct drives, while great for minimizing the mechanical complexity and backlash, are not always feasible depending on the design layout and the required output torque and speed characteristics for the indexing table. Therefore, the worm gear represents the best option among the choices given for precise and stable control in this context.