Holy **** Pat. I don't know if I'll be able to hold those tolerances or not, my guess is not.
Again, this is all a learning curve for me. I figured I would start out like I did with my tubing bender. Make some test bends and then use them to design the future bends based on needed radius and go from there.
Good plan Mike!!!
I would take 2 x 4 Coupons and scribe a line at 1.000 inch parallel to the 4 inch side and looking straight down at the edge of the tool align the scribe with the edge of the tool.
Make a 90° Bend and measure the length of the "Clamped" side first. Then add the other side and see how much is grew by subtracting the original flat size.
Now knowing the "Clamped" side Bend Line was at 1.000 inch you should be able to determine where the Bend would need to start if you wanted a 1.000 inch Outside to Outside (OS-OS).
Repeat again moving the Bend Line closer to the "Clamped" Edge by the amount determined. Measure again and you should be real close to a 1.000 OS_OS measurement.
You can double check the "Growth" by adding the 2 Flange Lengths and subtracting the overall flat length again.
My assumption would be the Growth will be close to @ 1/32 Inside Bend Radius:
.031 THK CRS = .059
.036 THK CRS = .062
.048 THK CRS = .080
.060 THK CRS = .095
Or @ 1/16 Inside Bend Radius:
.031 THK CRS = .072
.036 THK CRS = .075
.048 THK CRS = .093
.060 THK CRS = .108
The Growth will be the amount you want to subtract per bend from any flat layout out. The Growth is the Bend Deduction.
Not sure if the Inside Bend Radii will be effected by thickness and "springing" taking place in the Tooling/Brake??? There will be some deflection the thicker you go. How much is the question. I would be really interested in what the Material thickness effect is on the Inside Radius.
Once you get this all sorted out I am sure you can hold +/-.020 all day long. You definitely have the skill set and mechanically ability to make it happen.