Hello Scharette,
I’m new here
I require your help regarding a problem I’m encountering.
For the Lynxmotion 6DOF Biped Robot with no servos, the robot shop website specifies that either the Hitec HS-5475 or HS-5645 servos can be used for the robot. Will it be possible for me to use MG996R servos instead?
Thank you so much in advance for your help!
Ah, hello @RandomAcc812, welcome to the RobotShop community! 
On that front, @cbenson or @dialfonzo will probably know best what can be exchanged and still both fit mechanically and provide enough torque for the joints in question.
As a general note as long as the RC servomotors you are exchanging are of the same physical size (and you can provide the power), I’d recommend to try and use ones that will be around 20-30% of their rated stall torque when choosing an actuator for a robot joint or other specific purpose. This allows them to overheat less (and require less “breaks” to cool down) and also allow for better position control since they are not always straining.
@RandomAcc812 Welcome to the RobotShop Community. The brackets are made in such a way that many dimensions need to line up perfectly in order for servos to fit. Lynxmotion has only ever really done tests with Hitec servos, and the “standard sized” series is around because Hitec created a series of servos which effectively have the same dimensions (322, 422, 485, 5645 etc.). Based on the dimensions below, the two are quite similar, but there may be an issue with the top of the horn: The distance between the horn and the mount on the TowerPro is 21mm, whereas on the 645 it’s 17.3mm. Will that cause an issue in that the C-bracket will flex too much? Can’t say for certain.
