Flat layout of frustums and cones
First, please note that, apparently, the correct spelling is frustum, not frustrum. Hmmm…. You learn something new everyday!
Second, you might ask why am I talking about this? Isn’t this subject more appropriate to a blog on sheet metal work? Well, think about it. What if you’re designing a chair with a back that is laid out as a portion of a frustum? What if you want to make a brass lamp shade? How about a coopered pail? How about a dunce cap for your friends? I mean, the potential for this method is unlimited. Right? Okay. Maybe unlimited is a bit of a stretch. But understanding this layout may help visualize measurement of these shapes (or portions of them) in a number of scenarios. Remember diameter x 3.1417 = circumference.
If you should ever find yourself in the highly unlikely situation of having to layout a truncated cone, here’s an excellent tutorial site: http://leonjane.hubpages.com/hub/How-to-develop-a-Truncated-Cone#