OK,
Long story short, how would you draw the result of pulling a ball bearing through a hole in sheet metal? Basically I have a tank, and I need a flange in the tank that is 1-3/8" ID (1/16" stainless wall tank). I want the flange to be ~1/4" so you drill a 7/8" hole in the tank, and using a larger piece of pipe to pull against you pull a greased up 1-3/8" ball bearing through it welded to a threaded rod.
The result is a perfect spherical flange to weld a fitting onto. I would like this to be an automatic thing but I think I may end up drawing the profile of the flange with a revolve, and glueing that to a larger hole in the tank.
Any ideas?
BTW, this is a rediculously nifty trick for welding fittings onto tanks.
- Kuli