Cross Axle vs D-Shaft DC Motor | Cross Axle vs Hub Mount Servos

Quinn McRae Updated by Quinn McRae

The main difference between the types of DC Motors and Servos is a difference in how the motors connect to wheels and other accessories.

---DC Motors---

Note the shape of the above DC Motor’s shaft - it’s mostly cylindrically shaped with one flat edge, which we think of as a “D” shape. On the site, you'll see this referred to as DC Motor (D Shaft).Contrast that with the DC motor-dc motor (cross axle), which has a connector that is quite a bit different, like a Lego axle.


The 2 types of Servo motors have a similar dynamic. The servo (Hub Mount) , as the name implies, attaches to the a19 Servo Hub. They should be found together in any Kit that contains them. It is through the Servo Hub that you will attach to other accessories, like the Mechanical Arm (D Shaft) as pictured below.

The servo (cross axle) simplifies things by allowing users to connect directly from the servo's axle to accessories like the Mechanical Arm (Cross-Axle).

Please note, these two different types of motors are not interchangeable or possible to transform from one to another. We cannot ship just the plastic shaft caps because the operation of adhering them to the motor involves industrial strength glue which, if applied without precision equipment, could damage the motor. We also just don't have those parts on hand, so we are limited to selling and shipping the entire Bits.

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