I'll post a few photos to show some of the design differences from a Hossfeld. All the material, except for the pins and a couple of dies, is scrap I've had laying around. The pins are made from 1144 Stress Free and hardened. I've case hardened (using Kasenit) a couple of the bull nose pieces, but not the dies (yet).
I think the only real design difference in this bender is the use of the saddles and insert tools. By very carefully spacing holes in the forks (using a vertical mill) I was able to make the saddle pins fit tight in the forks. Then, using a piece of receiver tubing for a clamp, I'm able to make just about any fixture I need - and, these fixtures can have a wide range of adjustment. Lots of flexibility. For sure, the bending capacity is limited when using the saddles above the forks.
I've mounted the bender in a receiver hitch tube on my welding table (on lockable wheels). Time will tell whether this arrangement will offer enough torque. But, I can rotate the bender in a number of directions to change the position to get more leverage.
Part Two will be designing a scroll attachment. One that minimizes the amount of flat section on the interior scroll.