Curious Aardvark has the right idea. The amount of time involved to learn a scanning program and hardware would enable you to become a genius in so many different CAD programs. Like CA, I endorse the use of OpenSCAD, especially for something as straightforward as the pulleys you desire to duplicate.

Additionally, you'll find good support here and on the OpenSCAD forum for your project. Make a couple attempts and post your results if you don't get what you seek.

Consider especially to use parametric assignments for your build. That is, don't use:

Code:
cylinder(h = 10, d = 20);
Use instead:
Code:
center_boss_h = 10:
pulley_groove_d = 20;

cylinder(h = center_boss_h, d = pulley_groove_d);
The above method will allow you to make one change in the assignments and have the effects travel through your model construction.