This will work for hard to hold parts.
Just watched a video where the giuy had to machine a thin plate of aluminum, He wanted to use a very wide set fly cutter to clean up a cut path several inches across.
As you can imagine the cutting forces in a large cut are substantial.
But it was Thin so he couldn't squeeze it in a vice.
They clean the surfaces, using acetone, dry them and apply blue tape to the mating surfaces. Then the take a clean hunk of somethign round and burnish the blue tape pressing and rubbing it.
then they clean the tape and then apply Locktight pro super glue to one surface.
They squeeze them together a, lamp it let the glue set and then do the machining operation.
It Held~!!!!!!!!!!
here's the vid.