Making tube bending dies

[Toolmaker51]

Good directions in the video; duplicating bend allowance on paper. There are calculations that can be used but not all that handy, being that every material and form have their own peculiarities.
Nice trick too with the inside caliper doubling as an angle transfer gauge.
Somewhere here in HMT.net, I posted alterations to my HF bender; hard way dies for 5/8" flat stock. Essentially same as tubing, but slotted instead of radiused. One addition that's worthwhile is an adjustable stop instead of spacers. It's easy enough using two adjacent holes to secure a block, threaded to aim a setscrew at the pin on the swing frame.
A piece of round stock, drilled off center to be a cam, works too. Select a diameter and offset that goes from zero to a bit more than half the hole spacing.

To aid fellow builders and HF modders [along with shameless self-promotion] here is the hard way dieset. It's a good thread, my entry is #15 Homemade tools made with Harbor Freight tools