I was nosing around in a thread by Functional Artist and thought I would add a tip but I didn't want to hijack that thread.
I borrowed a photo from there
I had one of these for many years.
Worked great for what it is, but accuracy and repeatability was tricky.
I cut the beginning section from a cheapy tape measure and glued it along the length of the jack body.
I specifically used a SAE/metric tape but found the metric is much easier to use.
I made a pointer rod clamped to the end of the ram but without interfering with the various sized dies.
So the pointer would move across the scale with the jack rod extension.
Works fantastic for two ways.
1. Tubing tends to have some elasticity, bend it perfect, release pressure, and the bend flattens out to some extent.
My biggest challenge was to add a little bit of overbend without actually overbending.
So for example, make a bend. Say the scale reads say 120(numbers mean nothing but reference), release pressure and the bend comes up short, so then try 130 on second attempt, etc
It allows you to be conservative and home in on the perfect bend without overbending.
2. Also gives a great reference when doing multiple pieces with the same bend, or saving the info for the same bend in the future.
I borrowed a photo from there
I had one of these for many years.
Worked great for what it is, but accuracy and repeatability was tricky.
I cut the beginning section from a cheapy tape measure and glued it along the length of the jack body.
I specifically used a SAE/metric tape but found the metric is much easier to use.
I made a pointer rod clamped to the end of the ram but without interfering with the various sized dies.
So the pointer would move across the scale with the jack rod extension.
Works fantastic for two ways.
1. Tubing tends to have some elasticity, bend it perfect, release pressure, and the bend flattens out to some extent.
My biggest challenge was to add a little bit of overbend without actually overbending.
So for example, make a bend. Say the scale reads say 120(numbers mean nothing but reference), release pressure and the bend comes up short, so then try 130 on second attempt, etc
It allows you to be conservative and home in on the perfect bend without overbending.
2. Also gives a great reference when doing multiple pieces with the same bend, or saving the info for the same bend in the future.