I am trying to make a human or monkey skull shifter nob for my dad for his birthday because he does so much for me. I can use a 3D printer at school. Thank You!
modelleria metalli just uploaded a great OBJ file of a skull a week or two ago: skull special
Converting it into an STL should not be too difficult. If so, post back and I'll see how it goes.
You'll be able to scale the skull to meet your required size.
Add a center-mark to the bottom of the skull before 3D printing it.
After 3D printing, you'll need to decide how to finish it. I'd sand and fill it to a nice finish, then send it out for nickel plating. .006" of copper and nickel should be fine. It can then be buffed and polished.
The center-mark, you'll want to drill out. Then install a metal insert with the correct thread to match the existing shift knob. A Helicoil will work, but a heat-set insert bonded in with epoxy would be better in this situation.
Just keep in mind that you'll need to "time" the threads so the skull is looking in the correct direction once tightened down. Locktite on the threads will prevent it from coming loose.
The problem of course, is that the above process will cost 10x more than what you'd be able to buy an off the shelf shift knob for: http://www.amazon.com/s/ref=nb_sb_noss_2/179-5237962-2063337?url=search-alias%3Daps&field-keywords=skull+shift+knob
You could skip the nickel plating to save money, but it may look and feel like crap. The steering wheel and the shift knob are handled the most. Making them from high quality materials, and adequately designing them for comfort is very important.