Standoff

The standoff should be rigid and lightweight, so the motion of the piezo translates nicely in the tip motion, and insulated, so the flow of the tip does not leak elsewhere.
Some solutions include:

• A Plastruct cylinder by John Alexander
• A custom aluminium support with sapphire disk as insulator, by Dan Berard
• A fuse glass tube, by Vitor Barbosa
• A header pin on top of a glass piece, by MechRedPanda
• A MMCX connector on a PCB, by Dimsmary
• A ceramic standoff, by Jost Herkenhoff

The LiSPM uses a fuse glass tube. It’s cheap, light enough, rigid, easy to reproduce, and one of the best insulators. It also allows easy integration with the capacitive distance sensor due its regular radius and insulation across length.
To fix it in place, normal super glue is used.