I needed some clamps for holding word down on a sub plate that were less time consuming to adjust for workpiece thickness. This type of clamp is available commercially (Rite-Hite, etc) but at their simplest they can be made from tubing.
Sawing some scrap thick wall aluminum tube that was handy.
Sawn into thirds
Slotting on the Taig mill.
I radiused the ends and deburred on my belt grinder.
In an ideal world I’d make some washers that had a concave radius to match the pipe sections. But no need for now.