The PEEK column hardware has two specifications for threading:
1. The female outlet threading found on the outside of the end fittings, where the end plugs or extra-column tubing ferrules connect. This threading is standard 10-32 for all items regardless of internal diameter (ID). This accommodates capillary tubing that is 1/16″ outer diameter (OD).
2. The threading that connects the column tube to the end fittings. This varies depending on ID and is 1/4 – 28 for 2mm ID columns, 1/2 – 20 for 4.6mm, and 5/8 – 18 for 7.5mm.