In my view one of the prime reasons a rim has excess distortion and spring back is that the waist curve has not been shaped "and compressed" properly. To do that -- like the factory benders you need to have "male and female" forms that match the actual shape of the waist curve just holding the waist curve down in the center does not get it done -- its a compromise.
So, to supply a rim that our customers can work trouble free, KMG does a pre-bend on the waist curve and all our bending forms have matching waist curve cauls here's what they look like, as you can see they are made in segments, doweled together and covered with foil furnace tape -- simple to make, and again -- its worth the effort!



