Hello. MechE noob here. I'm an ECE guy and I'm apart of a group of students working on a solar car. I decided I wanted to get more mechanical experience so I joined one of the ME teams. However, before they let you work on real stuff they make you go through smaller projects. So my first smaller project was to make a mill handle to replace a broken one. I designed it in Solidworks. It is extremely simple, just two cylinders connected to each other with the radius of one much smaller so it can fit into a circular slot. My question is how to choose a material. I haven't the slightest idea what factors are at play here and how to go about deciding. I figure it will be plastic or aluminium but that's all I've got. Can I have some guidance as to how to go about this? Any help would be appreciated.