Hello, I'm new to this forum, and I hope you can help me. I'm working on a project to build my own motorized camera slider. Before I buy all the components, I want to be sure about my calculations. Mechanical engineering was never my forte, that's why I'm looking for help on this forum. As you can see in the sketch below, the slider will consist of 2 perpendicular steel shafts, that will carry the weight of sliding dolly (linear bearing + housing), camera and mount. Underneath between the shafts, there will be a timing belt that will be connected to the dolly. One of the pulleys of the timing belt will be connected to a stepper motor with a timing belt of selected transmission. http://shrani.si/t/2E/XD/1jG1hEmt/1/img001.jpg [Broken] - I apologize for the sketch. I'm not really good at drawing. 1) I'm interested in how to determine carrying capacity of the shaft, so I know which one to buy in respect to the selected load. And how to determine what would the deflection of the shaft be, so I can determine the size of supports for the shaft I need. 2) I also want to determine the power and torque needed of a stepper motor. - How to determine the maximum force acting on the stepper motor. How are the weight force, frictional force, force of static friction and force of acceleration acting in respect to each other. Are there any other forces I forgot to mention? I've chosen the wanted maximum speed, time of acceleration to maximum speed. - What is the effectiveness of the timing belt, and how to determine what torque is present in pulleys? I hope that's not too much to ask. I do hope we can find the solutions. Best regards, Alan J P.S.: English is not my mother language, so I apologize for any mistakes.