My RIDGID tube bender for 6mm tubes has a bending radius of 16 mm. The radius is measured to center of tube. When I make my own tube bender, I use a radius of 3x tube diameter and that works fine.

Jan

Just out of curiosity, as I didn't know the answer myself, I highlighted the relevant part of your question, and right clicked-search.
"minimum bending radius for 6 mm OD x 1mm wall thickness Stainless steel tube"

It took me straight here, to a pdf download which suggests 2x tube diameter.
https://www.listertube.com/links/tube-bending-design-guide/

Interesting document, overall, but see P14 to start

Bill

Peter, are you talking about the firebox end of the superheater? My commercially supplied stainless one has a large ish rad on both tubes which appear to have been welded to a spear point.

John

The bend radius you can achieve depends on how you bend it, supported or unsupported internally, as well as wall thickness, outside diameter and material.

This was the cardboard computer I used at work to decide what tooling needed buying if a new part was designed outside of the existing product designs.

I can't find it at the moment but you can figure out from the pictures what would be possible for an unsupported bore. Beyond that there are a number of ways to support the internal bore to avoid wrinkling that have been covered in a number of threads.

Martin C

Ø =?????