Servo is the key component. I use TowerPro [MG92B](http://www.towerpro.com.tw/product/mg92b/). It has metal gear (important!).
An hexapod requires 18 of them.
> The dimension of 3d printed part is highly depended on servo's dimension.<br>
> Modification is required if you want to use other alternative servo.
> TowerPro MG92B can be found on Ebay seller [servohorns959](https://www.ebay.com/usr/servohorns959), which is listed on TowerPro official website ([Link] (http://www.towerpro.com.tw/about-us-2/)). <br>I also got mime servo from him.
18 TowerPro [MG92B](http://www.towerpro.com.tw/product/mg92b/) are required.
> The dimension of 3d printed part is highly dependent on the servo's size. Modification is required if you want to use alternative servos.