Hello guys! This is my first post on this forum, and I really hope you guys can give me a hand here!

I've come into the possession of a Walkman cassette player made by Radio shack from the 80's, I think. The only issue with it is that it's missing the belt clip attachment! And if any of you have ever tried to stuff a massive cassette player in your pocket.. that doesn't work so well! So, I think my only option (other than to buy another one JUST for the belt clip) is to 3D print a replacement part. I myself don't own a 3D printer, but the university I attend has one I can use.

My question is, how do I go about designing the piece? I don't exactly have the dimensions of the object I want to create, but I've contacted a few people who are selling the item asking for photographs of the clip. I obviously have the mounts it fits into, so I can figure out exactly needs to happen there. But aside from all of that, how do I actually make a model of the object to be printed? I've done some game design, so I'm familiar with modeling programs like Blender, is it anything like that? What software should I use?

I think one of the biggest issues is knowing exactly what size to make this thing. How should I measure my walkman to assess the exact dimensions I need? Obviously the actual clip can be any shape really, but I'm concerned about the locking system, and getting all that measured up. I suppose I can just test fit, and sand down anything that doesn't fit, right?

For an item that will support a bulky object like this, I think it'll need to be a touch bit of plastic. Do you all have any recommendations as to how to print it/what plastics to use to insure that it will be stable enough, and I wont accidentally send my new toy crashing to the floor? As far as I can tell, there are three locking "tab" pieces that help lock the piece into place. Imagine a batter door cover, with the little tabs you slip into the main body of the thing to secure it. Exactly like that. I won't be in danger of snapping off a tab into the socket if I 3D print, right?

Here is what the mount looks like : http://i.imgur.com/xuBQfv8.jpg

Thanks in advance for any tips you guys can give me, I really appreciate it!